Battle of Britain

The Battle of Britain  (German: Luftschlacht um England, literally "Air battle for England") is the name given to the Second World War air campaign waged by the German Air Force (Luftwaffe) against the United Kingdom during the summer and autumn of 1940. The name is derived from a famous speech delivered by Prime Minister Winston Churchill in the House of Commons: "...the Battle of France is over. I expect that the Battle of Britain is about to begin."

The Battle of Britain was the first major campaign to be fought entirely by air forces, and was also the largest and most sustained aerial bombing campaign to that date. The objective of the campaign was to gain air superiority over the Royal Air Force (RAF), especially Fighter Command. From July 1940, coastal shipping convoys and shipping centres, such as Portsmouth, were the main targets; one month later the Luftwaffe shifted its attacks to RAF airfields and infrastructure. As the battle progressed the Luftwaffe also targeted aircraft factories and ground infrastructure. Eventually the Luftwaffe resorted to attacking areas of political significance and using terror bombing strategy.

The failure of Germany to achieve its objectives of destroying Britain's air defences, or forcing Britain to negotiate an armistice or an outright surrender, is considered its first major defeat and a crucial turning point in the Second World War. By preventing Germany from gaining air superiority, the battle ended the threat that Hitler would launch Operation Sea Lion, a proposed amphibious and airborne invasion of Britain.

Background
The early stages of the Second World War saw successful German invasions on the continent supported by Luftwaffe air power able to establish tactical air superiority. In early May 1940, the Norway Debate questioned the fitness for office of the British Prime Minister Neville Chamberlain. On 10 May, the Germans invaded France, and on the same day Winston Churchill became British Prime Minister. RAF Fighter Command was desperately short of trained pilots and aircraft, but despite the objections of its commander Hugh Dowding that this left home defences under-strength, Churchill sent fighter squadrons to support operations in France, where the RAF suffered heavy losses.

After the evacuation of British and French soldiers from Dunkirk and the French surrender on 22 June 1940, Hitler was mainly focused on the possibilities of invading the Soviet Union while believing that the British, defeated on the continent and without European allies, would quickly come to terms. Germans were so convinced of an imminent armistice that they began constructing street decorations for homecoming parades of victorious troops. Although the Foreign Secretary, Lord Halifax, and an element of British public and political sentiment favoured a negotiated peace with an ascendant Germany, Churchill and a majority of his Cabinet refused to consider an armistice with Hitler. Instead, Churchill used his skilful rhetoric to harden public opinion against capitulation, and to prepare the British for a long war. In his "This was their finest hour" speech on 18 June 1940, he said "the Battle of France is over. I expect that the Battle of Britain is about to begin."

After a series of victories, Germany ruled most of central Europe; from Poland to France, Denmark and Norway. Hitler hoped for a negotiated peace with Britain, but had made no preparations for amphibious assault on a hostile shore; at the time, the only forces with modern equipment and experience were the Japanese at the Battle of Wuhan. On 11 July, Grand Admiral Erich Raeder, Commander-in-Chief of the Kriegsmarine (German Navy), told Hitler that an invasion could only be contemplated as a last resort, and only after full air superiority had been achieved. The Kriegsmarine had been nearly crippled by the Norwegian Campaign, with many of its ships having been sunk or damaged, while the Royal Navy still had over 50 destroyers, 21 cruisers and eight battleships in the British Home Fleet. There was little the weakened Kriegsmarine could do to stop the Royal Navy from intervening. The only alternative was to use the Luftwaffe's dive bombers and torpedo bombers, which required air superiority to operate effectively. Grand Admiral Raeder said, "A powerful and effective air force might create conditions favourable for an invasion, whether it could was not in the Navy War Staff's province."

On 16 July, although he agreed with Raeder, Hitler ordered the preparation of a plan to invade Britain; he also hoped that news of the preparations would frighten Britain into peace negotiations. "Directive No. 16; On the Preparation of a Landing Operation against England" read, in part, as follows:

"Since England, despite its militarily hopeless situation, still has not shown any signs of being prepared to negotiate, I have decided to prepare a landing operation against England and, if necessary, carry it out. The objective of this operation is to eliminate the English home country as a base for the continuation of the war against Germany...

2) Included in these preparations is the bringing about of those preconditions which make a landing in England possible;

a) The English air force must have been beaten down to such an extent morally and in fact that it can no longer muster any power of attack worth mentioning against the German crossing. (italics added)"

All preparations were to be made by mid-August. For secrecy, this directive was only issued to Commanders in Chief, but Hermann Göring passed it on to his Luftwaffe Air Fleet commanders by coded radio messages, which were intercepted by Britain's Y-Service and successfully decrypted by Hut 6 at Bletchley Park.

The Kriegsmarine produced a draft plan for achieving a narrow beachhead near Dover. On 28 July the army responded that they wanted landings all along the South Coast of England. Hitler held a meeting of his army and navy chiefs on 31 July in his Berghof, and on 1 August the OKW (Oberkommando der Wehrmacht or "High Command of the Armed Forces") issued its plan. The plan, code named Unternehmen Seelöwe ("Operation Sea Lion"), was scheduled to take place in mid-September 1940. Seelöwe called for landings on the south coast of Great Britain, backed by an airborne assault. Neither Hitler nor OKW believed it would be possible to carry out a successful amphibious assault on Britain until the RAF had been neutralised. Raeder believed that air superiority might make a successful landing possible although it would be a risky operation and required "absolute mastery over the Channel by our air forces".

Conversely, Grand Admiral Karl Dönitz believed air superiority was "not enough". Dönitz stated, "we possessed neither control of the air or the sea; nor were we in any position to gain it." Some writers, such as Derek Robinson, have agreed with Dönitz. Robinson argues that the massive superiority of the Royal Navy over the Kriegsmarine would have made Sea Lion a disaster and the Luftwaffe could not have prevented decisive intervention by British cruisers and destroyers, even with air superiority. Williamson Murray argued that the task facing the Germans in summer 1940 was beyond their capabilities. The three German armed services were not capable of solving the problem of invading the British Isles. Murray contends that the Kriegsmarine had been effectively eliminated owing to heavy losses during the Norwegian Campaign. Murray states it is doubtful that the Kriegsmarine and Luftwaffe could have prevented the Royal Navy engaging the invasion fleet.

The Luftwaffe had not been represented at the Berghof, but Göring was confident that air victory was possible. Like many commanders in other air forces, including the RAF, he was convinced by the ideas of Giulio Douhet that "The bomber will always get through" and if attacks on military targets failed, bombing civilians could force the British government to surrender.

Opposing forces
The Luftwaffe faced a more capable opponent than any it had previously met: a sizeable, highly coordinated, well-supplied, modern air force.

Fighters
The Luftwaffe's Messerschmitt Bf 109E and Bf 110C fought against the RAF's workhorse Hurricane Mk I and the less numerous Spitfire Mk I. The Bf 109E had a better climb rate and was 10 - 30 mph faster than the Hurricane Mk I, depending on altitude. In spring and summer 1940, RAF fighters benefited from increased availability of 100 octane aviation fuel, which allowed their Merlin engines to generate significantly more power through the use of an Emergency Boost Override. In September 1940, the more powerful Mk IIa series 1 Hurricanes started entering service in small numbers. This version was capable of a maximum speed of 342 mph, some 25 - 30 mph more than the Mk I.

The performance of the Spitfire over Dunkirk came as a surprise to the Jagdwaffe, although the German pilots retained a strong belief that the 109 was the superior fighter. The British fighters were equipped with eight Browning .303 (7.7mm) machine guns, while most Bf 109Es had two 7.92mm machine guns supplemented by two 20mm wing cannons. The latter was a much more effective weapon than the .303, which was ineffectual against armour, and against all-metal aircraft structures at longer ranges. Many German planes returned to base despite large numbers of .303 hits. At some altitudes, the Bf 109 could outclimb the British fighter. It could also engage in vertical-plane negative-g manœuvres without the engine cutting out because its DB 601 inverted-V12 engine used fuel injection; this allowed the 109 to dive away from attackers more readily than the carburettor equipped Spitfire or Hurricane. On the other hand, the Bf 109E had a much larger turning circle than its two foes. In general, though, as Alfred Price noted in The Spitfire Story:

"...the differences between the Spitfire and the Me 109 in performance and handling were only marginal, and in a combat they were almost always surmounted by tactical considerations: which side had seen the other first, had the advantage of sun, altitude, numbers, pilot ability, tactical situation, tactical co-ordination, amount of fuel remaining, etc."

The Bf 109 was also used as a Jabo (jagdbomber, fighter-bomber)—the E-4/B and E-7 models could carry a 250 kg bomb underneath the fuselage. The Bf 109, unlike the Stuka, could fight on equal terms with RAF fighters after releasing its ordnance.

At the start of the battle, the twin-engined Messerschmitt Bf 110C long range Zerstörer ("Destroyer") was also expected to engage in air-to-air combat while escorting the Luftwaffe bomber fleet. Although the 110 was faster than the Hurricane and almost as fast as the Spitfire, its lack of manoeuvrability and acceleration meant that it was a failure as a long-range escort fighter. On 13 and 15 August, 13 and 30 aircraft were lost, the equivalent of an entire Gruppe, and the type's worst losses during the campaign. This trend continued with a further eight and fifteen lost on 16 and 17 August. Göring ordered the Bf 110 units to operate "where the range of the single-engined machines were not sufficient".

The most successful role of the Bf 110 during the battle was as a Schnellbomber (fast bomber). The Bf 110 usually used a shallow dive to bomb the target and escaped at high speed. One unit, Erprobungsgruppe 210 – initially formed as the service test unit (Erprobungskommando) for the emerging successor to the 110, the Me 210 – proved that the Bf 110 could still be used to good effect in attacking small or "pinpoint" targets.

The RAF's Boulton Paul Defiant had some initial success over Dunkirk because of its resemblance to the Hurricane; Luftwaffe fighters attacking from the rear were surprised by its unusual gun turret. However, during the Battle of Britain, this single-engined two-seater proved hopelessly outclassed. For various reasons, the Defiant lacked any form of forward-firing armament, and the heavy turret and second crewman meant it could not outrun or outmanœuvre either the Bf 109 or Bf 110. By the end of August, after disastrous losses, the aircraft was withdrawn from daylight service.

Fighter formations


In the late 1930s, Fighter Command expected to face only bombers over Britain, not single-engined fighters. With this in mind, a series of "Fighting Area Tactics" were formulated and rigidly adhered to, involving a series of manœuvres designed to concentrate a squadron's firepower to bring down bombers: with no apparent prospect of escorting fighters to worry about, RAF fighter pilots flew in tight, v-shaped sections ("vics") of three. These restricted squadrons to tight 12 aircraft formations composed of four sections in another tight "V". With this formation, only the squadron leader at the front was free to watch for the enemy; the other pilots had to concentrate on keeping station. RAF fighter training also emphasised by-the-book attacks by sections breaking away in sequence. Fighter Command recognised the weaknesses of this rigid structure early in the battle, but it was felt too risky to change tactics during the battle, because replacement pilots—often with only minimal flying time—could not be readily retrained, and inexperienced RAF pilots needed firm leadership in the air only rigid formations could provide. German pilots dubbed the RAF formations Idiotenreihen ("rows of idiots") because they left squadrons vulnerable to attack.

By contrast the, Luftwaffe formations employed a loose section of two (nicknamed the Rotte), based on a leader (Rottenführer) followed at a distance of about 183 m by his wingman (nicknamed the Rottenhund or Katschmareks), who also flew slightly higher and was trained always to stay with his leader. While the leader was free to search for enemy aircraft, and could cover his wingman's blind spots, his wingman could concentrate on searching the airspace in the leader's blind spots, behind and below. Attacking aircraft could be sandwiched between the two 109s. The rotte allowed the Rottenführer to concentrate on getting kills, but few wingmen were able to shoot down opposing aircraft, leading to some resentment in the lower ranks, where it was felt that the high scores of some Rottenführer came at the expense of their Katschmareks. During the Battle of Britain, a pilot who shot down 20 aircraft was automatically awarded the Ritterkreuz (Knight's Cross), to which was added Oak Leaves, Swords, and Diamonds for each additional 20 aircraft. Those pilots who appeared to be pursuing these awards were said to be suffering from Halsweh (a sore throat), a reference to the convention of wearing the decoration at the neck.

Two of these sections were usually teamed up into a Schwarm, where all the pilots could watch what was happening around them. Each Schwarm in a Staffel flew at staggered heights and with 183 m of room between them, making the formation difficult to spot at longer ranges and allowing for a great deal of flexibility. By utilising a tight "cross-over" turn, a Schwarm could quickly change direction.

The Bf 110s adopted the same Schwarm formation as the 109s, but were seldom able to use this to the same advantage. When attacked, Zerstörergruppen increasingly resorted to forming large "defensive circles". Each Bf 110 guarded the tail of the aircraft ahead of it. Göring ordered that they be renamed "offensive circles" in a vain bid to improve rapidly declining morale. These conspicuous formations were often successful in attracting RAF fighters that were sometimes "bounced" by high-flying Bf 109s. This led to the often repeated myth that the Bf 110s were escorted by Bf 109s. The Bf 110's most successful method of attack was the "bounce" from above.

Front line RAF pilots were acutely aware of the inherent deficiencies of their own tactics. A compromise was adopted whereby squadron formations used much looser formations with one or two "weavers" flying independently above and behind to provide increased observation and rear protection; these tended to be the least experienced men and were often the first to be shot down without the other pilots even noticing that they were under attack. During the battle, 74 Squadron under Squadron Leader Adolph "Sailor" Malan adopted a variation of the German formation called the "fours in line astern", which was a vast improvement on the old three aircraft "vic". Malan's formation was later generally used by Fighter Command.

Bombers


The Luftwaffe's four primary bombers were the Heinkel He 111, Dornier Do 17, and Junkers Ju 88 for level bombing, and the Junkers Ju 87 Stuka for diving attacks. The Heinkel He 111 was used in greater numbers than the others during the conflict and is better known, partly due to its distinctive wing shape. Each level bomber also had a few reconnaissance versions that were used during the battle.

Although successful in previous Luftwaffe engagements, the Stuka suffered heavy losses in the Battle of Britain, particularly on 18 August, due to its slow speed and vulnerability to fighter interception after the dive bombing. As a result of the losses and limited payload and range, Stuka units were largely removed from operations over England and concentrated on shipping instead until they were re-deployed to the Eastern Front in 1941. They returned on occasion, such as on 13 September to attack Tangmere airfield.

The remaining three bomber types differed in their capabilities; the Heinkel 111 was the slowest; the Ju 88 was the fastest once its mainly external bomb load was dropped; and the Do 17 had the smallest bomb load. All three bomber types suffered heavy losses from British fighters, but the Ju 88 disproportionately so. The German bombers required constant protection by the Luftwaffe's fighter force. There were not enough Bf 109Es to support more than 300–400 bombers on any given day. Later in the conflict, when night bombing became more frequent, all three were used. However, due to its reduced bomb load, the lighter Do 17 was used less than the He 111 and Ju 88 for this purpose.



On the British side, three bombers were mostly used on night operations against targets such as factories, invasion ports and railway centres; the Armstrong Whitworth Whitley, the Handley-Page Hampden and the Vickers Wellington were classified as heavy bombers by the RAF, although the Hampden was a medium bomber comparable to the He 111. The twin-engined Bristol Blenheim and the obsolescent single-engined Fairey Battle were both light bombers; the Blenheim was the most numerous of the aircraft equipping RAF Bomber Command and was used in attacks against shipping, ports, airfields and factories on the continent by day and by night. The Fairey Battle squadrons, which had suffered heavy losses in daylight attacks during the Battle of France, were brought up to strength with reserve aircraft and continued to operate at night in attacks against the invasion ports, until the Battle was withdrawn from UK front line service in October 1940.

Pilots
Before the war, the RAF's processes for selecting potential candidates were opened to men of all social classes through the creation of the RAF Volunteer Reserve in 1936 which "...was designed to appeal, to...young men...without any class distinctions..." The older squadrons of the Royal Auxiliary Air Force did retain some of their upper-class exclusiveness but their number were soon swamped by the newcomers of the RAFVR and by 1 1939 September 6646 pilots had been trained through the RAFVR.

By summer 1940, there were about 9,000 pilots in the RAF for approximately 5,000 aircraft, most of which were bombers. Fighter Command was never short of pilots, but the problem of finding sufficient numbers of fully trained fighter pilots became acute by mid-August 1940. With aircraft production running at 300 each week, only 200 pilots were trained in the same period. In addition, more pilots were allocated to squadrons than there were aircraft, as this allowed squadrons to maintain operational strength despite casualties and still provide for pilot leave. Another factor was that only about 30% of the 9,000 pilots were assigned to operational squadrons; 20% of the pilots were involved in conducting pilot training, and a further 20% were undergoing further instruction, like those offered in Canada and in Southern Rhodesia to the Commonwealth trainees, although already qualified. The rest were assigned to staff positions, since RAF policy dictated that only pilots could make many staff and operational command decisions, even in engineering matters. At the height of fighting, and despite Churchill's insistence, only 30 pilots were released to the front line from administrative duties.

For these reasons, and the permanent loss of 435 pilots during Battle of France alone with many more wounded, and others lost in Norway, the RAF had fewer experienced pilots at the start of the battle, and it was the lack of trained pilots in the fighting squadrons, rather than the lack of aircraft, that became the greatest concern for Air Chief Marshal Hugh Dowding, Commander of Fighter Command. Drawing from regular RAF forces and the Auxiliary Air Force and the Volunteer Reserve, the British could muster some 1,103 fighter pilots on 1 July. Replacement pilots, with little flight training and often no gunnery training, suffered high casualty rates.

The Luftwaffe could muster a larger number (1,450) of more experienced fighter pilots. Drawing from a cadre of Spanish Civil War veterans, they had comprehensive courses in aerial gunnery and instructions in tactics suited for fighter-versus-fighter combat. Training manuals also discouraged heroism, stressing the utmost importance of attacking only when the odds were in the pilot's favour. However, German fighter formations did not provide a sufficient reserve of pilots to allow for losses and leave, and the Luftwaffe was unable to produce enough pilots to prevent a decline in operational strength as the battle progressed.

Allies


The Royal Air Force roll of honour for the Battle of Britain recognises 595 non-British pilots (out of 2,936) as flying at least one authorised operational sortie with an eligible unit of the RAF or Fleet Air Arm between 10 July and 31 October 1940. These included 145 Poles, 127 New Zealanders, 112 Canadians, 88 Czechoslovaks, 10 Irish, 32 Australians, 28 Belgians, 25 South Africans, 13 French, 7 Americans, and one each from Jamaica, the British Mandate of Palestine, and Southern Rhodesia. "Altogether in the fighter battles, the bombing raids, and the various patrols flown between 10 July and 31 October 1940 by the Royal Air Force, 1495 aircrew were killed, of whom 449 were fighter pilots, 718 aircrew from Bomber Command, and 280 from Coastal Command. Among those killed were 47 airmen from Canada, 24 from Australia, 17 from South Africa, 35 from Poland, 20 from Czechoslovakia and six from Belgium. Forty-seven New Zealanders lost their lives, including 15 fighter pilots, 24 bomber and eight coastal aircrew. The names of these Allied and Commonwealth airmen are inscribed in a memorial book which rests in the Battle of Britain Chapel in Westminster Abbey. In the chapel is a stained glass window which contains the badges of the fighter squadrons which operated during the battle and the flags of the nations to which the pilots and aircrew belonged."

Axis
An element of the Italian Royal Air Force (Regia Aeronautica) called the Italian Air Corps (Corpo Aereo Italiano or CAI) first saw action in late October 1940. It took part in the latter stages of the battle, but achieved limited success. The unit was redeployed in early 1941.

Luftwaffe strategy
The Luftwaffe was devised to provide tactical support for the army on the battlefield. During the blitzkrieg offensives against Poland, Denmark and Norway and France and the Low Countries, the Luftwaffe had co-operated fully with the Wehrmacht. For the Battle of Britain however, the Luftwaffe had to operate in a strategic role, something for which it was unsuited. Its main task was to ensure air supremacy over southeast England, to pave the way for an invasion fleet.

The Luftwaffe regrouped after the Battle of France into three Luftflotten (Air Fleets) on Britain's southern and northern flanks. Luftflotte 2, commanded by Generalfeldmarschall Albert Kesselring, was responsible for the bombing of southeast England and the London area. Luftflotte 3, under Generalfeldmarschall Hugo Sperrle, targeted the West Country, Wales, the Midlands, and northwest England. Luftflotte 5, led by Generaloberst Hans-Jürgen Stumpff from his headquarters in Norway, targeted the north of England and Scotland. As the battle progressed, command responsibility shifted, with Luftflotte 3 taking more responsibility for the night-time Blitz attacks while the main daylight operations fell upon Luftflotte 2's shoulders.

Initial Luftwaffe estimates were that it would take four days to defeat the RAF Fighter Command in southern England. This would be followed by a four-week offensive during which the bombers and long-range fighters would destroy all military installations throughout the country and wreck the British aircraft industry. The campaign was planned to begin with attacks on airfields near the coast, gradually moving inland to attack the ring of sector airfields defending London. Later reassessments gave the Luftwaffe five weeks, from 8 August to 15 September, to establish temporary air superiority over England. To achieve this goal, Fighter Command had to be destroyed, either on the ground or in the air, yet the Luftwaffe had to be able to preserve its own strength to be able to support the invasion; this meant that the Luftwaffe had to maintain a high "kill ratio" over the RAF fighters. The only alternative to the goal of air superiority was a terror bombing campaign aimed at the civilian population, but this was considered a last resort and it was (at this stage of the battle) expressly forbidden by Hitler.

The Luftwaffe kept broadly to this scheme, but its commanders had differences of opinion on strategy. Sperrle wanted to eradicate the air defence infrastructure by bombing it. His counterpart, Kesselring, championed attacking London directly—either to bombard the British government into submission or to draw RAF fighters into a decisive battle. Göring did nothing to resolve this disagreement between his commanders, and only vague directives were set down during the initial stages of the battle, with Göring seemingly unable to decide upon which strategy to pursue. He seemed at times obsessed with maintaining his own power base in the Luftwaffe and indulging his outdated beliefs on air fighting, which would later lead to tactical and strategic errors.

Tactics
Luftwaffe tactics were influenced by their fighters. The Bf 110 proved too vulnerable to the nimble single-engined RAF fighters. This meant the bulk of fighter escort duties fell on the Bf 109. Fighter tactics were then complicated by bomber crews who demanded closer protection. After the hard-fought battles of 15 and 18 August, Göring met with his unit leaders. During this conference, the need for the fighters to meet up on time with the bombers was stressed. It was also decided that one bomber Gruppe could only be properly protected by several Gruppen of 109s. In addition Göring stipulated that as many fighters as possible were to be left free for Freie Jagd ("Free Hunts": a free-roving fighter sweep preceded a raid to try to sweep defenders out of the raid's path). The Ju 87 units, which had suffered heavy casualties, were only to be used under favourable circumstances. In early September, due to increasing complaints from the bomber crews about RAF fighters seemingly able to get through the escort screen, Göring ordered an increase in close escort duties. This decision shackled many of the Bf 109s to the bombers and, although they were more successful at protecting the bomber forces, casualties amongst the fighters mounted primarily because they were forced to fly and manoeuvre at reduced speeds.

The Luftwaffe consistently varied its tactics in its attempts to break through the RAF defences. It launched many Freie Jagd to draw up RAF fighters. RAF fighter controllers, however, were often able to detect these and position squadrons to avoid them, keeping to Dowding's plan to preserve fighter strength for the bomber formations. The Luftwaffe also tried using small formations of bombers as bait, covering them with large numbers of escorts. This was more successful, but escort duty tied the fighters to the bombers' slow speed and made them more vulnerable.

By September, standard tactics for raids had become an amalgam of techniques. A Freie Jagd would precede the main attack formations. The bombers would fly in at altitudes between 16000 ft and 20000 ft, closely escorted by fighters. Escorts were divided into two parts (usually Gruppen), some operating in close contact with the bombers, and others a few hundred yards away and a little above. If the formation was attacked from the starboard, the starboard section engaged the attackers, the top section moving to starboard and the port section to the top position. If the attack came from the port side the system was reversed. British fighters coming from the rear were engaged by the rear section and the two outside sections similarly moving to the rear. If the threat came from above, the top section went into action while the side sections gained height to be able to follow RAF fighters down as they broke away. If attacked, all sections flew in defensive circles. These tactics were skilfully evolved and carried out, and were extremely difficult to counter.

Adolf Galland noted: "We had the impression that, whatever we did, we were bound to be wrong. Fighter protection for bombers created many problems which had to be solved in action. Bomber pilots preferred close screening in which their formation was surrounded by pairs of fighters pursuing a zigzag course. Obviously, the visible presence of the protective fighters gave the bomber pilots a greater sense of security. However, this was a faulty conclusion, because a fighter can only carry out this purely defensive task by taking the initiative in the offensive. He must never wait until attacked because he then loses the chance of acting.

We fighter pilots certainly preferred the free chase during the approach and over the target area. This gives the greatest relief and the best protection for the bomber force."

The biggest disadvantage faced by Bf 109 pilots was that without the benefit of long-range drop tanks (which were introduced in limited numbers in the late stages of the battle), usually of 300 l capacity, the 109s had an endurance of just over an hour and, for the 109E, a 600 km range. Once over Britain, a 109 pilot had to keep an eye on a red "low fuel" light on the instrument panel: once this was illuminated, he was forced to turn back and head for France. With the prospect of two long flights over water, and knowing their range was substantially reduced when escorting bombers or during combat, the Jagdflieger coined the term Kanalkrankheit or "Channel sickness".

Intelligence
The Luftwaffe was ill-served by its lack of military intelligence about the British defences. The German intelligence services were fractured and plagued by rivalries; their performance was "amateurish". By 1940, there were few German agents operating in Great Britain and a handful of bungled attempts to insert spies into the country were foiled.

As a result of intercepted radio transmissions, the Germans began to realise that the RAF fighters were being controlled from ground facilities; in July and August 1939, for example, the airship Graf Zeppelin, which was packed with equipment for listening in on RAF radio and RDF transmissions, flew around the coasts of Britain. Although the Luftwaffe correctly interpreted these new ground control procedures, they were incorrectly assessed as being rigid and ineffectual. A British radar system was well known to the Luftwaffe from intelligence gathered before the war, but the highly developed "Dowding system" linked with fighter control had been a well-kept secret. Even when good information existed, such as a November 1939 Abwehr assessment of Fighter Command strengths and capabilities by Abteilung V, it was ignored if it did not match conventional preconceptions.

On 16 July 1940, Abteilung V, commanded by Oberstleutnant "Beppo" Schmid, produced a report on the RAF and on Britain's defensive capabilities which was adopted by the frontline commanders as a basis for their operational plans. One of the most conspicuous failures of the report was the lack of information on the RAF's RDF network and control systems capabilities; it was assumed that the system was rigid and inflexible, with the RAF fighters being "tied" to their home bases. An optimistic and, as it turned out, erroneous conclusion reached was:

"D. Supply Situation... At present the British aircraft industry produces about 180 to 300 first line fighters and 140 first line bombers a month. In view of the present conditions relating to production (the appearance of raw material difficulties, the disruption or breakdown of production at factories owing to air attacks, the increased vulnerability to air attack owing to the fundamental reorganisation of the aircraft industry now in progress), it is believed that for the time being output will decrease rather than increase.

In the event of an intensification of air warfare it is expected that the present strength of the RAF will fall, and this decline will be aggravated by the continued decrease in production."

Because of this statement, reinforced by another more detailed report, issued on 10 August, there was a mindset in the ranks of the Luftwaffe that the RAF would run out of frontline fighters. The Luftwaffe believed it was weakening Fighter Command at three times the actual attrition rate. Many times, the leadership believed Fighter Command's strength had collapsed, only to discover that the RAF were able to send up defensive formations at will.

Throughout the battle, the Luftwaffe had to use numerous reconnaissance sorties to make up for the poor intelligence. Reconnaissance aircraft (initially mostly Dornier Do 17s, but increasingly Bf 110s) proved easy prey for British fighters, as it was seldom possible for them to be escorted by Bf 109s. Thus, the Luftwaffe operated "blind" for much of the battle, unsure of its enemy's true strengths, capabilities, and deployments. Many of the Fighter Command airfields were never attacked, while raids against supposed fighter airfields fell instead on bomber or coastal defence stations. The results of bombing and air fighting were consistently exaggerated, due to inaccurate claims, over-enthusiastic reports and the difficulty of confirmation over enemy territory. In the euphoric atmosphere of perceived victory, the Luftwaffe leadership became increasingly disconnected from reality. This lack of leadership and solid intelligence meant the Germans did not adopt consistent strategy, even when the RAF had its back to the wall. Moreover, there was never a systematic focus on one type of target (such as airbases, radar stations, or aircraft factories); consequently, the already haphazard effort was further diluted.

Navigational aids
While the British were using radar for air defence more effectively than the Germans realised, the Luftwaffe attempted to press its own offensive with advanced radio navigation systems of which the British were initially not aware. One of these was Knickebein ("crooked leg"); this system was used at night and for raids where precision was required. It was rarely used during the Battle of Britain (see Reginald Victor Jones and Battle of the Beams).

Air-sea rescue
The Luftwaffe was much better prepared for the task of air-sea rescue than the RAF, specifically tasking the Seenotdienst unit, equipped with about 30 Heinkel He 59 floatplanes, with picking up downed aircrew from the North Sea, English Channel and the Dover Straits. In addition, Luftwaffe aircraft were equipped with life rafts and the aircrew were provided with sachets of a chemical called fluorescein which, on reacting with water, created a large, easy-to-see, bright green patch. In accordance with the Geneva Convention, the He 59s were unarmed and painted white with civilian registration markings and red crosses. Nevertheless, RAF aircraft attacked these aircraft, as some were escorted by Bf 109s.

After single He 59s were forced to land on the sea by RAF fighters, on 1 and 9 July respectively, a controversial order was issued to the RAF on 13 July; this stated that from 20 July, Seenotdienst aircraft were to be shot down. One of the reasons given by Churchill was:

"We did not recognise this means of rescuing enemy pilots so they could come and bomb our civil population again... all German air ambulances were forced down or shot down by our fighters on definite orders approved by the War Cabinet."

The British also believed that their crews would report on convoys, the Air Ministry issuing a communiqué to the German government on 14 July that Britain was

"unable, however, to grant immunity to such aircraft flying over areas in which operations are in progress on land or at sea, or approaching British or Allied territory, or territory in British occupation, or British or Allied ships. Ambulance aircraft which do not comply with the above will do so at their own risk and peril"

The white He 59s were soon repainted in camouflage colours and armed with defensive machine guns. Although another four He 59s were shot down by RAF aircraft, the Seenotdienst continued to pick up downed Luftwaffe and Allied aircrew throughout the battle, earning praise from Adolf Galland for their bravery.

The Dowding System
British defence was based on the "Dowding System", the complex infrastructure of detection, command, and control that ran the battle. It was named after its chief architect, Air Chief Marshal Sir H.C.T. "Stuffy" Dowding, the leader of RAF Fighter Command and the one important person in Britain—and perhaps the world—who had not believed the 1930s orthodoxy that "the bomber will always get through". Much of the air defence system had been originally set up from 1917 by Major General E B Ashmore. Dowding built upon and modernised many of the features of this system, including the use of two-way radio and the Royal Observer Corps (ROC). However, the core of Dowding's system was implemented by Dowding himself: the use of Radio Direction Finding (RDF, later called radar, for radio detection and ranging) was at his behest, and its use, supplemented by information by the ROC, was crucial to the RAF's ability to efficiently intercept incoming German aircraft. He also insisted on having the radar operators linked via telephone (whose wires were laid deep underground with concrete anti-bomb protection) to an operational centre: Fighter Command control at Bentley Priory. During the battle, several Coastal Command and Fleet Air Arm units came under Fighter Command control.

Groups
The British airspace was divided up into four Groups.
 * 10 Group defended Wales and the West Country and was commanded by Air Vice-Marshal Sir Quintin Brand.
 * 11 Group covered the southeast of England and the critical approaches to London and was commanded by New Zealander Air Vice-Marshal Keith Park from the No. 11 Group Fighter Command Operations Room in the underground bunker at RAF Uxbridge, now known as the Battle of Britain Bunker.
 * 12 Group defended the Midlands and East Anglia and was led by Air Vice-Marshal Trafford Leigh-Mallory.
 * 13 Group covered the north of England, Scotland and Northern Ireland and was commanded by Air Vice-Marshal Richard Saul.

Control systems
Usually the first indications of incoming air raids were received by the Chain Home Radio Direction Finding (RDF) facilities which were located around the coastlines of Great Britain. In most circumstances, RDF could pick up formations of Luftwaffe aircraft as they organised over their own airfields. Once the raiding aircraft moved inland over England, the formations were also plotted by the Observer Corps. The information from RDF and the Observer Corps were sent through to the main operations room of Fighter Command Headquarters at Bentley Priory. The plots were assessed to determine whether they were "hostile" or "friendly". If hostile, the information was sent to the main "operations room", which was in a large underground bunker.

Here the course information of each raid was plotted by WAAFs who received information by a telephone system. Additional intelligence was provided by the "Y" Service radio posts, which monitored enemy radio transmissions, and the "Ultra" decoding centre based at Bletchley Park. Colour-coded counters representing each raid were placed on a large table, which had a map of Britain overlaid and squared off with a British Modified Grid. The colour of counter to use for a new sighting was determined by the time of the sighting, the proper colour being indicated by the minute hand of the sector clock. As the plots of the raiding aircraft moved, the counters were pushed across the map by magnetic "rakes". This system enabled the main "Fighter Controller" (usually of squadron leader rank) and Dowding to see quickly where each formation was heading and allowed an estimate to be made of possible targets. The age of the information was readily apparent from the colour of the counter. Because of the simplicity of the system, decisions could be made quickly and easily.

Apart from the controller, most of the room and map information was operated by members of the WAAF. Before the war, there was still a great deal of doubt about the ability of women to stand up to battle conditions, with many airwomen employed on front-line RDF stations and aerodromes. Experience during the battle proved that such doubts were unfounded and the contribution of the WAAFs became essential to the RAF in its control and communications systems and in many other duties.

This information was simultaneously sent to the headquarters of each Group (for example, RAF Uxbridge for 11 Group), where it was "filtered" through a filter room (that is, collated, cross-checked and simplified), before being sent through to another operations room, housed in the Battle of Britain Bunker. Because Group had tactical control of the battle, the operations room was different in layout from the one at Bentley Priory. The main map on the plotting table represented the Group command area and its associated airfields. Extensive radio and telephone equipment transmitted and received a constant flow of information from the various sector airfields as well as the Observer Corps, AA Command and the navy. The "Duty fighter controller" was (for example in 11 Group) Park's personal representative, whose job was to control how and when each raid would be dealt with. He ordered the squadrons airborne and positioned them as he thought best. Timing was of the essence, because "(e)ach minute of unnecessary delay waiting to make absolutely sure that the raid was coming in meant about 2,000 feet of vital altitude our fighters would not have when they met the enemy." (Wing Commander Lord Willoughby de Broke, Senior Fighter Controller, Uxbridge.)

Each Group room had a "tote board" which showed each squadron available to that group. The tote board had a system of lights which enabled the controllers to see the squadron status: Released (not available); Available (airborne in 20 minutes); Readiness (airborne in 5 minutes); Standby (pilots in cockpit, airborne in 2 minutes); Airborne and moving into position; Enemy sighted; Ordered to land; Landed and refuelling/rearming. Next to the tote board, where it could be clearly seen, was a weather board which showed the state of the weather around each airfield. It was the responsibility of the WAAF plotters to continually update the tote and weather boards.

A vital role was played by the telephone engineers of the GPO "who worked all hours repairing communications, installing completely new facilities in the emergency centres, and keeping the nervous system of Fighter Command functioning..." (Air Commodore Eric Roberts, Commander Middle Wallop Sector in 1940)

Despite appearances, the Groups were not mutually supporting; Park, for instance, could only request – not demand – assistance from Brand (who usually co-operated), or from Leigh-Mallory (who often prevaricated). This was because Dowding had never issued standing orders to assist, nor had he created a method to co-ordinate it.

There was a further problem in that the aircraft were not assigned equitably between Groups. While the most effective RAF fighter was the Spitfire, 70% of 11 Group aircraft were Hurricanes. "In total, less than a third of Britain's best fighters were operating in the key sector."

Sectors
The Group areas were subdivided into Sectors; each commanding officer was assigned between two and four squadrons. Sector Stations, comprising an aerodrome with a "Sector operations room", were the heart of this organisation, and they were also responsible for operating satellite aerodromes to which squadrons could be dispersed. The operations rooms duplicated those at the Group HQs, although they were on a smaller scale and most were still housed in brick, single-storey, tile-roofed structures above ground, where they were vulnerable to attack. By 1940, most were semi-protected by an earth bank or "blast wall" surrounding them which reached as high as the eaves. Fortunately for Fighter Command, Luftwaffe Intelligence was unaware of the importance of these rooms and most were left alone. The control rooms at Biggin Hill were destroyed by a raid on 31 August, but this was due to a chance bomb hit. Their vulnerability in time of war was appreciated and new airfields built during the expansion programme of the 1930s had new, bombproof Mk II, L-shaped structures. As a further precaution, emergency control rooms were set up in different locations away from the airfields, with small loss in efficiency; RAF Kenley, for example, could use an alternative room housed in a butcher's shop in nearby Caterham. The plotting table was laid out with a map of the sector and its airfields, and the tote and weather boards reflected this more localised information.

When ordered by their Group HQ, the sector stations would "scramble" their squadrons into the air. Once airborne, the squadrons would be directed by radio-telephone (R/T) from their sector station. Squadrons could be ordered to patrol airfields or vital targets or be "vectored" to intercept incoming raids. As well as directing the fighter squadrons, Sector stations also controlled the anti-aircraft batteries in their area; an army officer sat beside each fighter controller and directed the gun crews when to open fire and, if RAF aircraft flew into the gun-zones, ordered the guns to cease fire.

Limitations
Though it was the most sophisticated air defence system in the world at that time, the Dowding System had many limitations, including, but not often stressed, its emphatic need for qualified ground maintenance personnel, many of whom had received their training under the Aircraft Apprentice scheme instituted by Hugh Trenchard. RDF (radar) was subject to significant errors and the Observer Corps had difficulties tracking raids at night and in bad weather. R/T (radio telephone) communications with airborne fighters were restricted because the standard radio set used by RAF fighters at the beginning of the battle was the TR9D HF set, which operated over two selectable frequencies in the band 4.3–6.6 Megahertz (MHz); the RAF soon realised that this equipment was limited in the range at which it could receive and transmit radio signals because of its limited power. In addition, the increase in the number of civil, military and foreign HF-band radio transmitters since the adoption of the TR9 meant that the signal often suffered from distortion and interference, making clear communication with the RAF fighters difficult. It was also restricted to a single frequency per squadron, making inter-squadron communication impossible. Finally, the system for tracking RAF fighters, known as HF/DF or "Huff-Duff", restricted sectors to a maximum of four squadrons in the air. The addition of IFF, "Pipsqueak", while a welcome help in identifying RAF aircraft, took up another radio channel.

In late September 1940, VHF T/R Type 1133 radios started replacing the TR9s. These had first been fitted to Spitfires of 54 and 66 Squadrons starting in October 1939, but production delays with the improved T/R 1143 set meant the bulk of Spitfires and Hurricanes were not fitted with this equipment until October 1940. The reception was much clearer over a longer range, and controllers and pilots had a wider range of communications channels to choose from.

Effect of signals intelligence
It is unclear how much the British intercepts of the Enigma cipher, used for high-security German radio communications, affected the battle. Ultra, the information obtained from Enigma intercepts, gave the highest echelons of the British command a view of German intentions. According to F. W. Winterbotham, who was the senior Air Staff representative in the Secret Intelligence Service, Ultra helped establish the strength and composition of the Luftwaffe's formations, the aims of the commanders and provided early warning of some raids. In early August it was decided that a small unit would be set up at Fighter Command headquarters (Stanmore), which would process the flow of information from Bletchley and provide Dowding only with the most essential Ultra material; thus the Air Ministry did not have to send a continual flow of information to Stanmore, preserving secrecy, and Dowding was not inundated with non-essential information. Keith Park and his controllers were also told about Ultra. In a further attempt to camouflage the existence of Ultra, Dowding created a unit named No. 421 (Reconnaissance) Flight RAF. This unit (which later became No. 91 Squadron RAF), was equipped with Hurricanes and Spitfires and sent out aircraft to search for and report Luftwaffe formations approaching England. In addition the radio listening service (known as Y Service), monitoring the patterns of Luftwaffe radio traffic, contributed considerably to the early warning of raids.

Air-sea rescue
One of the biggest oversights of the entire system was the lack of a proper air-sea rescue organisation. The RAF had started organising a system in 1940 with High Speed Launches (HSLs) based on flying boat bases and at a number of overseas locations, but it was still believed that the amount of cross-Channel traffic meant that there was no need for a rescue service to cover these areas. Downed pilots and aircrew, it was hoped, would be picked up by any boats or ships which happened to be passing by. Otherwise the local life boat would be alerted, assuming someone had seen the pilot going into the water.

RAF aircrew were issued with a life jacket, nicknamed the "Mae West" but in 1940 it still required manual inflation, which was almost impossible for someone who was injured or in shock. The waters of the English Channel and Dover Straits are cold, even in the middle of summer, and clothing issued to RAF aircrew did little to insulate them against these freezing conditions. The RAF also imitated the German practice of issuing fluorescein. A conference in 1939 had placed air-sea rescue under Coastal Command. Because a number of pilots had been lost at sea during the "Channel Battle", on 22 August, control of RAF rescue launches was passed to the local naval authorities and 12 Lysanders were given to Fighter Command to help look for pilots at sea. In all some 200 pilots and aircrew were lost at sea during the battle. No proper air-sea rescue service was formed until 1941.

Tactics
The weight of the battle fell upon 11 Group. Keith Park's tactics were to dispatch individual squadrons to intercept raids. The intention was to subject incoming bombers to continual attacks by relatively small numbers of fighters and try to break up the tight German formations. Once formations had fallen apart, stragglers could be picked off one by one. Where multiple squadrons reached a raid the procedure was for the slower Hurricanes to tackle the bombers while the more agile Spitfires held up the fighter escort. This ideal was not always achieved, resulting in occasions when Spitfires and Hurricanes reversed roles. Park also issued instructions to his units to engage in frontal attacks against the bombers, which were more vulnerable to such attacks. Again, in the environment of fast moving, three-dimensional air battles, few RAF fighter units were able to attack the bombers from head-on.

During the battle, some commanders, notably Leigh-Mallory, proposed squadrons be formed into "Big Wings," consisting of at least three squadrons, to attack the enemy en masse, a method pioneered by Douglas Bader.

Proponents of this tactic claimed interceptions in large numbers caused greater enemy losses while reducing their own casualties. Opponents pointed out the big wings would take too long to form up, and the strategy ran a greater risk of fighters being caught on the ground refuelling. The big wing idea also caused pilots to overclaim their kills, due to the confusion of a more intense battle zone. This led to the belief big wings were far more effective than they were.

The issue caused intense friction between Park and Leigh-Mallory, as 12 Group was tasked with protecting 11 Group's airfields whilst Park's squadrons intercepted incoming raids. However, the delay in forming up Big Wings meant the formations often did not arrive at all or until after German bombers had hit 11 Group's airfields. Dowding, to highlight the problem of the Big Wing's performance, submitted a report compiled by Park to the Air Ministry on 15 November. In the report, he highlighted that during the period of 11 September – 31 October, the extensive use of the Big Wing had resulted in just 10 interceptions and one German aircraft destroyed, but his report was ignored. Post-war analysis agrees Dowding and Park's approach was best for 11 Group.

Dowding's removal from his post in November 1940 has been blamed on this struggle between Park and Leigh-Mallory's daylight strategy. However, the intensive raids and destruction wrought during the Blitz damaged both Dowding and Park in particular, for the failure to produce an effective night-fighter defence system, something for which the influential Leigh-Mallory had long criticised them.

Bomber and Coastal Command contributions
Bomber Command and Coastal Command aircraft flew offensive sorties against targets in Germany and France during the battle. After the initial disasters of the war, with Vickers Wellington bombers shot down in large numbers attacking Wilhelmshaven and the slaughter of the Fairey Battle squadrons sent to France, it became clear that Bomber Command would have to operate mainly at night to achieve any results without incurring very high losses. From 15 May 1940, a night time bomber campaign was launched against the German oil industry, communications, and forests/crops, mainly in the Ruhr area.

As the threat mounted, Bomber Command changed targeting priority on 3 June 1940 to attack the German aircraft industry. On 4 July, the Air Ministry gave Bomber Command orders to attack ports and shipping. By September, the build-up of invasion barges in the Channel ports had become a top priority target. On 7 September, the government issued a warning that the invasion could be expected within the next few days and, that night, Bomber Command attacked the Channel ports and supply dumps. On 13 September, they carried out another large raid on the Channel ports, sinking 80 large barges in the port of Ostend. 84 barges were sunk in Dunkirk after another raid on 17 September and by 19 September, almost 200 barges had been sunk. The loss of these barges may have contributed to Hitler's decision to postpone Operation Sea Lion indefinitely. The success of these raids was in part because the Germans had few Freya radar stations set up in France, so that air defences of the French harbours were not nearly as good as the air defences over Germany; Bomber Command had directed some 60% of its strength against the Channel ports.

The Bristol Blenheim units also raided German-occupied airfields throughout July to December 1940, both during daylight hours and at night. Although most of these raids were unproductive, there were some successes; on 1 August, five out of 12 Blenheims sent to attack Haamstede and Evere (Brussels) were able to bomb, destroying or heavily damaging three Bf 109s of II./JG 27 and apparently killing a Staffelkapitän identified as a Hauptmann Albrecht von Ankum-Frank. Two other 109s were claimed by Blenheim gunners. Another successful raid on Haamstede was made by a single Blenheim on 7 August which destroyed one 109 of 4./JG 54, heavily damaged another and caused lighter damage to four more.

There were some missions which produced an almost 100% casualty rate amongst the Blenheims; one such operation was mounted on 13 August 1940 against a Luftwaffe airfield near Aalborg in north-eastern Denmark by 12 aircraft of 82 Squadron. One Blenheim returned early (the pilot was later charged and due to appear before a court martial, but was killed on another operation), the other 11, which reached Denmark, were shot down, five by flak and six by Bf 109s. Of the 33 crewmen who took part in the attack, 20 were killed and 13 captured.

As well as the bombing operations, Blenheim-equipped units had been formed to carry out long-range strategic reconnaissance missions over Germany and German-occupied territories. In this role, the Blenheims again proved to be too slow and vulnerable against Luftwaffe fighters, and they took constant casualties.

Coastal Command directed its attention towards the protection of British shipping, and the destruction of enemy shipping. As invasion became more likely, it participated in the strikes on French harbours and airfields, laying mines, and mounting numerous reconnaissance missions over the enemy-held coast. In all, some 9,180 sorties were flown by bombers from July to October 1940. Although this was much less than the 80,000 sorties flown by fighters, bomber crews suffered about half the total number of casualties borne by their fighter colleagues. The bomber contribution was, therefore, much more dangerous on a loss-per-sortie comparison.

Bomber, reconnaissance, and antisubmarine patrol operations continued throughout these months with little respite and none of the publicity accorded to Fighter Command. In his famous 20 August speech about "The Few", praising Fighter Command, Churchill also made a point of mentioning Bomber Command's contribution, adding that bombers were even then striking back at Germany; this part of the speech is often overlooked, even today. The Battle of Britain Chapel in Westminster Abbey lists in a Roll of Honour, 718 Bomber Command crew members, and 280 from Coastal Command who were killed between 10 July and 31 October.

Phases of the battle
The Battle can be roughly divided into four phases:
 * 10 July – 11 August: Kanalkampf, ("the Channel battles").
 * 12–23 August: Adlerangriff ("Eagle Attack"), the early assault against the coastal airfields.
 * 24 August – 6 September: the Luftwaffe targets the airfields. The critical phase of the battle.
 * 7 September onwards: the day attacks switch to British towns and cities.

Channel battles
The Kanalkampf comprised a series of running fights over convoys in the English Channel. It was launched partly because Kesselring and Sperrle were not sure about what else to do, and partly because it gave German aircrews some training and a chance to probe the British defences. Dowding could only provide minimal shipping protection, and these battles off the coast tended to favour the Germans, whose bomber escorts had the advantage of altitude and outnumbered the RAF fighters. From 9 July reconnaissance probing by Dornier Do 17 bombers put a severe strain on RAF pilots and machines, with high RAF losses to Bf 109s. When nine 141 Squadron Defiants went into action on 19 July six were lost to Bf 109s before a squadron of Hurricanes intervened. On 25 July a coal convoy and escorting destroyers suffered such heavy losses to attacks by Stuka dive bombers that the British Admiralty decided convoys should travel at night: the RAF shot down 16 raiders but lost 7 aircraft. By 8 August 18 coal ships and 4 destroyers had been sunk, but the Navy was determined to send a convoy of 20 ships through rather than move the coal by railway. After repeated Stuka attacks that day, six ships were badly damaged, four were sunk and only four reached their destination. The RAF lost 19 fighters and shot down 31 German aircraft. The Navy now cancelled all further convoys through the Channel and sent the cargo by rail. However, these early combat encounters provided both sides with experience.

Main assault
The main attack upon the RAF's defences was code-named Adlerangriff ("Eagle Attack").

Poor weather delayed Adlertag ("Eagle Day") until 13 August 1940. On 12 August, the first attempt was made to blind the Dowding system, when aircraft from the specialist fighter-bomber unit Erprobungsgruppe 210 attacked four radar stations. Three were briefly taken off the air but were back working within six hours. The raids appeared to show that British radars were difficult to knock out. The failure to mount follow-up attacks allowed the RAF to get the stations back on the air, and the Luftwaffe neglected strikes on the supporting infrastructure, such as phone lines and power stations, which could have rendered the radars useless, even if the towers themselves (which were very difficult to destroy) remained intact.

Adlertag opened with a series of attacks, led again by Epro 210, on coastal airfields used as forward landing grounds for the RAF fighters, as well as 'satellite airfields' (including Manston and Hawkinge). As the week drew on, the airfield attacks moved further inland, and repeated raids were made on the radar chain. 15 August was "The Greatest Day" when the Luftwaffe mounted the largest number of sorties of the campaign. Luftflotte 5 attacked the north of England. Believing Fighter Command strength to be concentrated in the south, raiding forces from Denmark and Norway ran into unexpectedly strong resistance. Inadequately escorted by Bf 110s, bombers were shot down in large numbers. North East England was attacked by 65 Heinkel 111s escorted by 34 Messerschmitt 110s, and RAF Great Driffield was attacked by 50 unescorted Junkers 88s. Out of 115 bombers and 35 fighters sent, 16 bombers and 7 fighters were destroyed. As a result of these casualties, Luftflotte 5 did not appear in strength again in the campaign.

18 August, which had the greatest number of casualties to both sides, has been dubbed "The Hardest Day". Following the grinding battles of 18 August, exhaustion and the weather reduced operations for most of a week, allowing the Luftwaffe to review their performance. "The Hardest Day" had sounded the end for the Ju 87 in the campaign. This veteran of Blitzkrieg was too vulnerable to fighters to operate over Britain, and to preserve the Stuka force, Göring withdrew them from the fighting. This removed the main Luftwaffe precision-bombing weapon and shifted the burden of pinpoint attacks on the already-stretched Erpro 210. The Bf 110 proved too clumsy for dogfighting with single-engined fighters, and its participation was scaled back. It would only be used when range required it or when sufficient single-engined escort could not be provided for the bombers.

Göring made yet another fateful decision: to order more bomber escorts at the expense of free-hunting sweeps. To achieve this, the weight of the attack now fell on Luftflotte 2, and the bulk of the Bf 109s in Luftflotte 3 were transferred to Kesselring's command, reinforcing the fighter bases in the Pas-de-Calais. Stripped of its fighters, Luftflotte 3 would concentrate on the night bombing campaign. Göring, expressing disappointment with the fighter performance thus far in the campaign, also made sweeping changes in the command structure of the fighter units, replacing many Geschwaderkommodore with younger, more aggressive pilots like Adolf Galland and Werner Mölders.

Finally, Göring stopped the attacks on the radar chain. These were seen as unsuccessful, and neither the Reichsmarschall nor his subordinates realised how vital the Chain Home stations were to the defence. It was known that radar provided some early warning of raids, but the belief among German fighter pilots was that anything bringing up the "Tommies" to fight was to be encouraged.

Battle
Göring ordered attacks on aircraft factories on 19 August 1940; on 23 August 1940 he ordered that RAF airfields be attacked. That evening an attack was mounted on a tyre factory in Birmingham. Raids on airfields continued through 24 August, and Portsmouth was hit by a major attack. That night, several areas of London were bombed; the East End was set ablaze and bombs landed on central London. Some historians believe that these bombs were dropped accidentally by a group of Heinkel He 111s which had failed to find their target; this account has been contested. In retaliation, the RAF bombed Berlin on the night of 25–26 August, and continued bombing raids on Berlin. Göring's pride was hurt, as he had previously claimed the British would never be able to bomb the city. The attacks enraged Hitler, who ordered retaliatory attacks on London.

From 24 August onwards, the battle was a fight between Kesselring's Luftflotte 2 and Park's 11 Group. The Luftwaffe concentrated all their strength on knocking out Fighter Command and made repeated attacks on the airfields. Of the 33 heavy attacks in the following two weeks, 24 were against airfields. The key sector stations were hit repeatedly: Biggin Hill and Hornchurch four times each; Debden and North Weald twice each. Croydon, Gravesend, Rochford, Hawkinge and Manston were also attacked in strength. Coastal Command's Eastchurch was bombed at least seven times because it was believed to be a Fighter Command aerodrome. At times these raids caused some damage to the sector stations, threatening the integrity of the Dowding system.

To offset some losses, some 58 Fleet Air Arm fighter pilot volunteers were seconded to RAF squadrons, and a similar number of former Fairey Battle pilots were used. Most replacements from Operational Training Units (OTUs) had as little as nine hours flying time and no gunnery or air-to-air combat training. At this point, the multinational nature of Fighter Command came to the fore. Many squadrons and personnel from the air forces of the Dominions were already attached to the RAF, including top level commanders – Australians, Canadians, New Zealanders, Rhodesians and South Africans. In addition, there were other nationalities represented, including Free French, Belgian and a Jewish pilot from the British mandate of Palestine.

They were bolstered by the arrival of fresh Czechoslovak and Polish squadrons. These had been held back by Dowding, who mistakenly thought non-English speaking aircrew would have trouble working within his control system. However, Polish and Czech fliers proved to be especially effective. The pre-war Polish Air Force had lengthy and extensive training, and high standards; with Poland conquered and under brutal German occupation, the pilots of No. 303 (Polish) Squadron, the highest-scoring Allied unit, were strongly motivated. Josef František, a Czech regular airman who had flown from the occupation of his own country to join the Polish and then French air forces before arriving in Britain, flew as a guest of 303 Squadron and was ultimately credited with the highest "RAF score" in the Battle of Britain.

The RAF had the advantage of fighting over home territory. Pilots who bailed out of their downed aircraft could be back at their airfields within hours, while if low on fuel and/or ammunition they could be immediately rearmed. One RAF pilot interviewed in late 1940 had been shot down five times during the Battle of Britain, but was able to crash land in Britain or bail out each time. For Luftwaffe aircrews, a bailout over England meant capture – in the critical August period the Luftwaffe lost almost exactly as many pilots as prisoners as were killed – while parachuting into the English Channel often meant drowning or death from exposure. Morale began to suffer, and Kanalkrankheit ("Channel sickness") – a form of combat fatigue – began to appear among the German pilots. Their replacement problem was even worse than the British.

Impact of offensive
The effect of the German attacks on airfields is unclear. According to Stephen Bungay Dowding, in a letter to Hugh Trenchard accompanying Park's report on the period 8 August – 10 September 1940, states that the Luftwaffe "achieved very little" in the last week of August and the first week of September. The only Sector Station to be shut down operationally was Biggin Hill, and it was non-operational for just two hours. Dowding admitted 11 Group's efficiency was impaired but, despite serious damage to some airfields, only two out of 13 heavily attacked airfields were down for more than a few hours. The German refocus on London was not critical.

Retired air marshal Peter Dye, head of the RAF Museum, discussed the logistics of the battle in 2000 and 2010, dealing specifically with the single-seat fighters. Dye contends that not only was British aircraft production replacing aircraft, but replacement pilots were keeping pace with losses. The number of pilots in RAF Fighter Command increased during July, August and September. The figures indicate the number of pilots available never decreased. From July, 1,200 were available. In 1 August, 1,400 were available. Just over that number were in the field by September. In October the figure was nearly 1,600. By 1 November 1,800 were available. Throughout the battle, the RAF had more fighter pilots available than the Luftwaffe. Although the RAF's reserves of single seat fighters fell during July, the wastage was made up for by an efficient Civilian Repair Organisation (CRO), which by December had repaired and put back into service some 4,955 aircraft, and by aircraft held at Air Servicing Unit (ASU) airfields.

Richard Overy agrees with Dye and Bungay. Overy asserts only one airfield was temporarily put out of action and "only" 103 pilots were lost. British fighter production produced 496 new aircraft in July and 467 in August, and another 467 in September (not counting repaired aircraft), covering the losses of August and September. Overy indicates the number of serviceable and total strength returns reveal an increase in fighters from 3 August to 7 September, 1,061 on strength and 708 serviceable to 1,161 on strength and 746 serviceable. Moreover, Overy points out that the number of RAF fighter pilots grew by one-third between June and August 1940. Personnel records show a constant supply of around 1,400 pilots in the crucial weeks of the battle. In the second half of September it reached 1,500. The shortfall of pilots was never above 10 percent. The Germans never had more than between 1,100 and 1,200 pilots, a deficiency of up to one-third. "If Fighter Command were 'the few', the German fighter pilots were fewer".

Other scholars assert that this period was the most dangerous of all. In The Narrow Margin, published in 1961, historians Derek Wood and Derek Dempster believed that the two weeks from 24 August to 6 September represented a real danger. According to them, from 24 August to 6 September 295 fighters had been totally destroyed and 171 badly damaged, against a total output of 269 new and repaired Spitfires and Hurricanes. They assert that 103 pilots were killed or missing and 128 were wounded, which represented a total wastage of 120 pilots per week out of a fighting strength of just fewer than 1,000. They conclude that during August no more than 260 fighter pilots were turned out by OTUs and casualties in the same month were just over 300. A full squadron establishment was 26 pilots whereas the average in August was 16. In their assessment, the RAF was losing the battle. Denis Richards, in his 1953 contribution to the official British account History of the Second World War, agreed that lack of pilots, especially experienced ones, was the RAF's greatest problem. He states that between 8 and 18 August 154 RAF pilots were killed, severely wounded, or missing, while only 63 new pilots were trained. Available aircraft was also a serious issue. While its reserves during the Battle of Britain never declined to a half dozen planes as some later claimed, Richards describes 24 August to 6 September as the critical period because during these two weeks Germany destroyed far more aircraft through its attacks on 11 Group's southeast bases than Britain was producing. Three more weeks of such a pace would indeed have exhausted aircraft reserves. Germany had seen heavy losses of pilots and aircraft as well, however, thus its shift to nighttime attacks in September. On 7 September RAF aircraft losses fell below British production and remained so until the end of the war.

By this point Hitler was becoming impatient with the Luftwaffe. On 14 September, General Hans Jeschonnek, Luftwaffe Chief of Staff, persuaded Hitler for a last chance to defeat the RAF and sought permission to launch attacks on civilian residential areas to cause mass panic. Hitler refused the latter, perhaps unaware of just how much damage had already been done to civilian targets, as he wanted to reserve for himself the right to unleash the terror weapon. Political will was to be broken by the collapse of the material infrastructure, the weapons industry, along with the destruction of stocks of fuel and food. On 16 September, Göring ordered the air fleets to begin the new phase of the battle. Within two months, American journalist Ralph Ingersoll published a book after a visit to Britain which stated that "Adolf Hitler met his first defeat in eight years"&mdash;which might "go down in history as a battle as important as Waterloo or Gettysburg"&mdash;by reducing the intensity of the Blitz after 15 September. According to Ingersoll, "[a] majority of responsible British officers who fought through this battle believe that if Hitler and Goering had had the courage and the resources to lose 200 planes a day for the next five days, nothing could have saved London"; instead, "[the Luftwaffe's] morale in combat is definitely broken, and the RAF has been gaining in strength each week."

Raids on British cities


Hitler's No. 17 Directive, issued on 1 August 1940 on the conduct of war against England specifically prohibited Luftwaffe from conducting terror raids on its own initiative, and reserved the right of ordering terror attacks as means of reprisal for the Führer himself:

"The war against England is to be restricted to destructive attacks against industry and air force targets which have weak defensive forces... The most thorough study of the target concerned, that is vital points of the target, is a pre-requisite for success. It is also stressed that every effort should be made to avoid unnecessary loss of life amongst the civilian population."

The Luftwaffe offensive against Britain had included numerous raids on major ports since August, but Hitler had issued a directive London was not to be bombed save on his sole instruction. However, on the afternoon of 15 August, Hauptmann Walter Rubensdörffer leading Erprobungsgruppe 210 mistakenly bombed the Croydon airfield (on the outskirts of London) instead of the intended target, RAF Kenley; this was followed on the night of 23/24 August by the accidental bombing of Harrow, also on the outskirts of London, as well as raids on Aberdeen, Bristol, and South Wales. The focus on attacking airfields had also been accompanied by a sustained bombing campaign which began on 24 August with the largest raid so far, killing 100 in Portsmouth, and that evening the first night raid on London as described above. On 25 August 1940, 81 bombers of Bomber Command were sent out to raid industrial and commercial targets in Berlin. Clouds prevented accurate identification and the bombs fell across the city, causing some casualties amongst the civilian population as well as damage to residential areas. Continuing RAF raids on Berlin in retaliation led to Hitler withdrawing his directive, and on 3 September Göring planned to bomb London daily, with Kesselring's enthusiastic support, having received reports the average strength of RAF squadrons was down to five or seven fighters out of 12 and their airfields in the area were out of action. Hitler issued a directive on 5 September to attack cities including London. In his speech delivered on 4 September 1940, Hitler threatened to obliterate (ausradieren) British cities if British bombing runs against Germany did not stop.

On 7 September, a massive series of raids involving nearly four hundred bombers and more than six hundred fighters targeted docks in the East End of London, day and night. The raids were codenamed Operation Loge. The RAF anticipated attacks on airfields and 11 Group rose to meet them, in greater numbers than the Luftwaffe expected. The first official deployment of 12 Group's Big Wing took twenty minutes to gain formation, missing its intended target, but encountering another formation of bombers while still climbing. They returned, apologetic about their limited success, and blamed the delay on being requested too late. Fighter Command had been at its lowest ebb, short of men and machines, and the break from airfield attacks allowed them to recover. 11 Group had considerable success in breaking up daytime raids. 12 Group repeatedly disobeyed orders and failed to meet requests to protect 11 Group airfields, but their experiments with increasingly large Big Wings had some successes. The Luftwaffe began to abandon their morning raids, with attacks on London starting late in the afternoon for 57 consecutive nights of attacks.

The most damaging aspect to the Luftwaffe of the change in targets (to London) was the increase in range. The Bf 109 escorts had a limited fuel capacity, and by the time they arrived had only 10 minutes of flying time before they had to turn for home. This left many raids undefended by fighter escorts.

On 14 September, Hitler chaired a meeting with the OKW staff. Göring was absent in France, as he had decided to direct the decisive part of the battle from there, and left Erhard Milch to deputise for him. At the meeting Hitler raised the question, "Should we call it off altogether?". Hitler had accepted that an invasion with massive air cover was no longer possible. Instead he opted to try to crush British morale, while maintaining the threat of invasion. Hitler concluded this might result in "eight million going mad" (referring to the population of London in 1940), which would "cause a catastrophe" for the British. In those circumstances, Hitler said, "even a small invasion might go a long way". At this point, Hitler was against cancelling the invasion as "the cancellation would reach the ears of the enemy and strengthen his resolve".

On 15 September, two massive waves of German attacks were decisively repulsed by the RAF, with every aircraft of 11 Group being used on that day. The total casualties on this critical day were 60 German and 26 RAF aircraft shot down. The German defeat caused Hitler to order, two days later, the postponement of preparations for the invasion of Britain. Henceforth, in the face of mounting losses in men, aircraft and the lack of adequate replacements, the Luftwaffe switched from daylight to nighttime bombing. The air battles on 15 September became known as the Battle of Britain Day.

On 27 September, a Junkers Ju 88 returning from a raid on London was shot down in Kent, resulting in the Battle of Graveney Marsh, the last action between British and foreign military forces on British mainland soil.

On 13 October, Hitler again postponed the invasion "until the spring of 1941"; however, the invasion never happened, and October is regarded as the month regular bombing of Britain ended. It was not until Hitler's Directive 21 was issued, on 18 December 1940, that the threat of invasion finally dissipated.

During the battle, and for the rest of the war, an important factor in keeping public morale high was the continued presence in London of King George VI and his wife Queen Elizabeth. When war broke out in 1939, the King and Queen decided to stay in London and not flee to Canada, as had been suggested. George VI and Elizabeth officially stayed in Buckingham Palace throughout the war, although they often spent weekends at Windsor Castle to visit their daughters, Elizabeth (the future queen) and Margaret. Buckingham Palace was damaged by bombs which landed in the grounds on 10 September and, on 13 September, more serious damage was caused by two bombs which destroyed the Royal Chapel. The royal couple were in a small sitting room about 80 yards from where the bombs exploded. On 24 September, in recognition of the bravery of civilians, King George VI inaugurated the award of the George Cross.

Attrition statistics
Overall, by 2 November, the RAF fielded 1,796 pilots, an increase of over 40% from July 1940's count of 1,259 pilots. Based on German sources (from a Luftwaffe intelligence officer Otto Bechtle attached to KG 2 in February 1944) translated by the Air Historical Branch, Stephen Bungay asserts German fighter and bomber "strength" declined without recovery, and that from August – December 1940, the German fighter and bomber strength declined by 30 and 25 percent. In contrast, Williamson Murray, asserts (using translations by the Air Historical Branch) that 1,380 German bombers were on strength on 29 June 1940, 1,420 bombers on 28 September, 1,423 level bombers on 2 November and 1,393 bombers on 30 November 1940. In July – September the number of Luftwaffe pilots available fell by 136, but the number of operational pilots had shrunk by 171 by September. The training organisation of the Luftwaffe was failing to replace losses. German fighter pilots, in contrast to popular perception, were not afforded training or rest rotations unlike their British counterparts. The first week of September accounted for 25 per cent of the Fighter Command, and 24 per cent of the Luftwaffe's overall losses. Between the dates 26 August – 6 September, on only one day (1 September) did the Germans destroy more aircraft than they lost. Losses were 325 German and 248 British.

Luftwaffe losses for August numbered 774 aircraft to all causes, representing 18.5 per cent of all combat aircraft at the beginning of the month. Fighter Command's losses in August were 426 fighters destroyed, amounting to 40 per cent of 1,061 fighters available on 3 August. In addition, 99 bombers and 27 other types were destroyed between 1 and 29 August.

From July to September, the Luftwaffe's loss records indicate the loss of 1,636 aircraft, 1,184 to enemy action. This represented 47 per cent of the initial strength of single-engined fighters, 66 per cent of twin-engined fighters, and 45 per cent of bombers. This indicates the Germans were running out of aircrews as well as aircraft.

Throughout the battle, the Germans greatly underestimated the size of the RAF and the scale of British aircraft production. Across the Channel, the Air Intelligence division of the Air Ministry consistently overestimated the size of the German air enemy and the productive capacity of the German aviation industry. As the battle was fought, both sides exaggerated the losses inflicted on the other by an equally large margin. However, the intelligence picture formed before the battle encouraged the German Air Force to believe that such losses pushed Fighter Command to the very edge of defeat, while the exaggerated picture of German air strength persuaded the RAF that the threat it faced was larger and more dangerous than was the case. This led the British to the conclusion that another fortnight of attacks on airfields might force Fighter Command to withdraw their squadrons from the south of England. The German misconception, on the other hand, encouraged first complacency, then strategic misjudgement. The shift of targets from air bases to industry and communications was taken because it was assumed that Fighter Command was virtually eliminated.

Between the 24 August and 4 September, German serviceability rates, which were acceptable at Stuka units, were running at 75% with Bf 109s, 70% with bombers and 65% with Bf 110s, indicating a shortage of spare parts. All units were well below established strength. The attrition was beginning to affect the fighters in particular." By 14 September, the Luftwaffe's Bf 109 Geschwader possessed only 67 percent of their operational crews against authorised aircraft. For Bf 110 units it was 46 per cent; and for bombers it was 59 per cent. A week later the figures had dropped to 64 per cent, 52 per cent and 52 per cent. Serviceability rates in Fighter Command's fighter squadrons, between the 24 August and 7 September, were listed as: 64.8% on 24 August; 64.7% on 31 August and 64.25% on 7 September 1940.

Due to the failure of the Luftwaffe to establish air supremacy, a conference assembled on 14 September at Hitler's headquarters. Hitler concluded that air superiority had not yet been established and "promised to review the situation on 17 September for possible landings on 27 September or 8 October. Three days later, when the evidence was clear that the German Air Force had greatly exaggerated the extent of their successes against the RAF, Hitler postponed Sea Lion indefinitely."

Aftermath
The Battle of Britain marked the first defeat of Hitler's military forces, with air superiority seen as the key to victory. Pre-war theories led to exaggerated fears of strategic bombing, and British public opinion was invigorated by having come through the ordeal. Had Britain lost the battle or capitulated either the Nazis or the Soviets would have dominated Europe, with the US being able to do little to change things.

For the British, Fighter Command had achieved a great victory in successfully carrying out Sir Thomas Inskip's 1937 air policy of preventing the Germans from knocking Britain out of the war. The Fighter Command was so successful that the conclusion to Churchill's famous 'Battle of Britain' speech made in the House of Commons on 18 June, has come to refer solely to them: "...if the British Empire and its Commonwealth lasts for a thousand years, men will still say, 'This was their finest hour.'"

The Battle also signalled a significant shift in American opinion. During the battle, many people from the US accepted the view promoted by Joseph Kennedy, the American ambassador in London, and believed that Great Britain could not survive. However, Roosevelt wanted a second opinion, and sent "Wild Bill" Donovan on a brief visit to Britain; he became convinced Britain would survive and should be supported in every possible way.

Both sides in the battle made exaggerated claims of numbers of enemy aircraft shot down. In general, claims were two to three times the actual numbers, because of the confusion of fighting in dynamic three-dimensional air battles. Postwar analysis of records has shown that between July and September, the RAF claimed 2,698 kills, while the Luftwaffe fighters claimed 3,198 RAF aircraft downed. Total losses, and start and end dates for recorded losses, vary for both sides. Luftwaffe losses from 10 July to 30 October 1940 total 1,652 aircraft, including 229 twin- and 533 single-engined fighters. In the same period, RAF Fighter Command aircraft losses number 1,087, including 53 twin-engined fighters. To the RAF figure should be added 376 Bomber Command and 148 Coastal Command aircraft conducting bombing, mining, and reconnaissance operations in defence of the country.

The Luftwaffe had 1,380 bombers on 29 June 1940. By 2 November 1940, this had increased to 1,423, and to 1,511 by 21 June 1941, prior to Operation Barbarossa, but showing a drop of 200 from 1,711 reported on 11 May 1940. 1,107 single- and 357 twin-engined daylight fighters were reported on strength prior to the Battle on 29 June 1940, compared to 1,440 single- and 188 twin-engined fighters, plus 263 night fighters, on 21 June 1941.

There is a consensus among historians that the Luftwaffe simply could not crush the RAF. Stephen Bungay described Dowding and Park's strategy of choosing when to engage the enemy whilst maintaining a coherent force as vindicated. The RAF proved to be a robust and capable organisation which was to use all the modern resources available to it to the maximum advantage. Richard Evans wrote:

"Irrespective of whether Hitler was really set on this course, he simply lacked the resources to establish the air superiority that was the sine qua non-of a successful crossing of the English Channel. A third of the initial strength of the German air force, the Luftwaffe, had been lost in the western campaign in the spring. The Germans lacked the trained pilots, the effective fighter planes, and the heavy bombers that would have been needed."

The Germans launched some spectacular attacks against important British industries, but they could not destroy the British industrial potential, and made little systematic effort to do so. Hindsight does not disguise the fact the threat to Fighter Command was very real, and for the participants it seemed as if there was a narrow margin between victory and defeat. Nevertheless, even if the German attacks on the 11 Group airfields which guarded southeast England and the approaches to London had continued, the RAF could have withdrawn to the Midlands out of German fighter range and continued the battle from there. The victory was as much psychological as physical. Writes Alfred Price: "The truth of the matter, borne out by the events of 18 August is more prosaic: neither by attacking the airfields, nor by attacking London, was the Luftwaffe likely to destroy Fighter Command. Given the size of the British fighter force and the general high quality of its equipment, training and morale, the Luftwaffe could have achieved no more than a Pyrrhic victory. During the action on 18 August it had cost the Luftwaffe five trained aircrewmen killed, wounded or taken prisoner, for each British fighter pilot killed or wounded; the ratio was similar on other days in the battle. And this ratio of 5:1 was very close to that between the number of German aircrew involved in the battle and those in Fighter Command. In other words the two sides were suffering almost the same losses in trained aircrew, in proportion to their overall strengths. In the Battle of Britain, for the first time during the Second World War, the German war machine had set itself a major task which it patently failed to achieve, and so demonstrated that it was not invincible. In stiffening the resolve of those determined to resist Hitler the battle was an important turning point in the conflict."

The British victory in the Battle of Britain was achieved at a heavy cost. Total British civilian losses from July to December 1940 were 23,002 dead and 32,138 wounded, with one of the largest single raids on 19 December 1940, in which almost 3,000 civilians died.

The brilliant leadership of Dowding and Keith Park in successfully proving their theories of air defence, however, had created enmity among RAF senior commanders and both were sacked from their posts in the immediate aftermath of the battle.

The end of the battle allowed Britain to rebuild its military forces and establish itself as an Allied stronghold. Britain later served as a base from which the Liberation of Western Europe was launched.

Battle of Britain Day
Winston Churchill summed up the effect of the battle and the contribution of Fighter Command with the words, "Never in the field of human conflict was so much owed by so many to so few". Pilots who fought in the Battle have been known as The Few ever since; at times being specially commemorated for on "Battle of Britain Day" the 15th of September. On this day in 1940, the Luftwaffe embarked on their largest bombing attack yet, forcing the engagement of the entirety of the RAF in defence of London and the South East, which resulted in a decisive victory in favour of Britain that proved to mark a turning point in Britain's favour.

Within the Commonwealth, Battle of Britain Day has been observed more usually on the third Sunday in September, and even as the 2nd Thursday of September in some areas in the British Channel Islands.

Film
The story of the battle was documented in, amongst many others, the 1969 film Battle of Britain, which drew many respected British actors to act key figures of the battle, including Sir Laurence Olivier as Hugh Dowding and Trevor Howard as Keith Park. It also starred Michael Caine, Christopher Plummer and Robert Shaw as Squadron Leaders. Former participants of the battle served as technical advisors including Douglas Bader, James Lacey, Robert Stanford Tuck, Adolf Galland and Dowding himself. An Italian film around the same time titled Eagles Over London (1969) also featured the Battle of Britain.

It was also the subject of the 1941 Allied propaganda film Churchill's Island, winner of the first-ever Academy Award for Documentary Short Subject.

In 2010, actor Julian Glover played a 101-year-old Polish veteran RAF pilot in the short film, Battle for Britain.

General

 * Allen, Hubert Raymond "Dizzy", Wing Commander, RAF. Who Won the Battle of Britain? London: Arthur Barker, 1974. ISBN 0-213-16489-2.
 * Bishop, Edward. Their Finest Hour: The Battle of Britain 1940. London: Ballantine Books, 1968.
 * Buckley, John. Air Power in the Age of Total War. London: UCL Press, 1999. ISBN 1-85728-589-1.
 * Buell, Thomas. The Second World War: Europe and the Mediterranean. New York: Square One Publishers, 2002. ISBN 978-0-7570-0160-4.
 * Bungay, Stephen. The Most Dangerous Enemy: A History of the Battle of Britain. London: Aurum Press, 2000. ISBN 1-85410-721-6 (hardcover), 2002, ISBN 1-85410-801-8 (paperback).
 * Collier, Richard. Eagle Day: The Battle of Britain, 6 August – 15 September 1940. London: Pan Books, 1968.
 * Churchill, Winston S. The Second World War – Their Finest Hour (Volume 2). London: Cassell, 1949.
 * Churchill, Winston S. The Second World War – The Grand Alliance (Volume 3). Bantam Books, 1962.
 * Corum, James. The Luftwaffe: Creating the Operational Air War, 1918–1940. Kansas University Press, 1997. ISBN 0-7006-0836-2
 * Deighton, Len. Fighter: The True Story of the Battle of Britain. London: Pimlico, 1996. (Originally published: London: Jonathan Cape, 1977.) ISBN 0-7126-7423-3.
 * Deighton, Len. Battle of Britain. London: Cape, 1980. ISBN 0-224-01826-4.
 * de Zeng, Henry L., Doug G. Stankey and Eddie J. Creek. Bomber Units of the Luftwaffe 1933–1945: A Reference Source, Volume 1. Hersham, Surrey, UK: Ian Allen Publishing, 2007. ISBN 978-1-85780-279-5.
 * Dönitz, Karl. Ten years and Twenty Days. New York: Da Capo Press, First Edition, 1997. ISBN 0-306-80764-5.
 * Dye, Air Commodore Peter J. "Logistics and the Battle of Britain". Air Force Journal of Logistics No. 24, Vol 4, Winter 2000.
 * Ellis, John. Brute Force: Allied Strategy and Tactics in the Second World War. London: Andre Deutsch, 1990. ISBN 0-8264-8031-4.
 * Evans, Michael. "Never in the field of human conflict was so much owed by so many to... the Navy." The Times, 24 August 2006. Retrieved 3 March 2007.
 * Halpenny, Bruce Barrymore. Action Station 4: Military Airfields of Yorkshire. Cambridge, UK: Patrick Stevens, 1984. ISBN 0-85059-532-0.
 * Harding, Thomas. "Battle of Britain was won at sea." The Telegraph, 25 August 2006. Retrieved 25 August 2006.
 * Holland, James. The Battle of Britain. London: Bantam, 2010. ISBN 978-0-593-05913-5.
 * Hooton, E.R. Luftwaffe at War: Blitzkrieg in the West, Vol. 2. London: Chevron/Ian Allen, 2007. ISBN 978-1-85780-272-6.
 * Hough, Richard and Denis Richards. The Battle of Britain: The Greatest Air Battle of World War II. New York: W.W. Norton & Co Inc, 2007. ISBN 978-0-393-02766-2.
 * Irving, David. The Rise and Fall of the Luftwaffe: The Life of Field Marshal Erhard Milch. Dorney, Windsor, UK: Focal Point Publications, 1974. ISBN 978-0-297-76532-5.
 * Keegan, John. The Second World War London: Pimlico, 1997. ISBN 978-0-7126-7348-8.
 * Kieser, Egbert. Operation Sea Lion; The German Plan to Invade Britain 1940. London: Cassel Military Paperbacks, 1999. ISBN 0-304-35208-X.
 * Kieser, Egbert. Unternehmen Seelöwe: Die geplante Invasion in England 1940 (in German). Berlin, Germany: Becthle, 2000. ISBN 3-7628-0457-5.
 * Korda, Michael. With Wings Like Eagles: The Untold Story of the Battle of Britain. New York: Harper Perennial, 2010. ISBN 978-0-06-112536-2.
 * Macksey, Kenneth. Invasion: The German Invasion of England, July 1940. London: Greenhill Books, 1990. ISBN 0-85368-324-7.
 * Mason, Francis K.Battle Over Britain: A History of the German Air Assaults on Great Britain, 1917-18 and July-December 1940, and the Development of Air Defences Between the World Wars. New York: Doubleday, 1969. ISBN 978-0-90192-800-9.
 * Murray, Willamson. Strategy for Defeat. The Luftwaffe 1935–1945. Princeton, New Jersey: University Press of the Pacific, 2002. ISBN 0-89875-797-5.
 * Overy, Richard. The Battle of Britain: The Myth and the Reality. New York: W.W. Norton, 2001. ISBN 0-393-02008-8 (hardcover); 2002, ISBN 0-393-32297-1(paperback).
 * Owen, R.E, New Zealanders with the Royal Air Force Government Printer, Wellington, New Zealand 1953.
 * Peszke, Michael Alfred. "A Synopsis of Polish-Allied Military Agreements During World War Two." The Journal of Military History, Volume 44, No. 3, October 1980, pp. 128–134.
 * Ponting, Clive. 1940: Myth and reality. Chicago: Ivan R. Dee, 1991. ISBN 978-1-56663-036-8.
 * Pope, Stephan. "Across the Ether: Part One". Aeroplane, Vol. 23, No. 5, Issue No. 265, May 1995.
 * Price, Alfred. The Hardest Day: 18 August 1940. New York: Charles Scribner's Sons, 1980. ISBN 0-684-16503-1.
 * Ramsay, Winston, ed. The Blitz Then and Now: Volume 1. London: Battle of Britain Prints International Ltd, 1987. ISBN 0-900913-45-2.
 * Raeder, Erich. Erich Rader, Grand Admiral. New York: Da Capo Press. United States Naval Institute, 2001. ISBN 0-306-80962-1.
 * Ramsay, Winston, ed. The Blitz Then and Now: Volume 2. London: Battle of Britain Prints International Ltd, 1988. ISBN 0-900913-54-1.
 * Ramsay, Winston, ed. The Battle of Britain Then and Now Mk V. London: Battle of Britain Prints International Ltd, 1989. ISBN 0-900913-46-0.
 * Robinson, Derek. Invasion, 1940: Did the Battle of Britain Alone Stop Hitler? New York: Carroll & Graf, 2005. ISBN 0-7867-1618-5.
 * Shulman, Milton. Defeat in the West. London: Cassell, 2004 (First edition 1947). ISBN 0-304-36603-X.
 * Shirer, William. The Rise and Fall of the Third Reich: A History of Nazi Germany. London: Ballantine, 1991. ISBN 978-0-449-21977-5.
 * Taylor, A.J.P. and S.L. Mayer, eds. A History Of World War Two. London: Octopus Books, 1974. ISBN 0-7064-0399-1.
 * Terraine, John. The Right of the Line: The Royal Air Force in the European War, 1939–1945. New York: Sceptre, 1985. ISBN 0-340-41919-9.
 * Terraine, John. A Time for Courage: The Royal Air Force in the European War, 1939–1945. London: Macmillan, 1985. ISBN 978-0-02-616970-7.
 * Winterbotham, F.W. The Ultra Secret. London: Futura Publications Limited, 1975. ISBN 0-86007-268-1 (paperback).
 * Wood, Derek and Derek Dempster. The Narrow Margin: The Battle of Britain and the Rise of Air Power, 1930–1949. London: Pen & Sword, 2003, First edition 1961. ISBN 978-0-85052-915-9.
 * Wright, Gordon. The Ordeal of Total War: 1939–1945. New York: Harper & Row, 1968.

Autobiographies and biographies

 * Deere, Alan C. Nine Lives. London: Hodder Paperbacks Ltd for Coronet Books, 1974. ISBN 0-340-01441-5.
 * Duncan Smith, Group Captain W.G.G. Spitfire into Battle. London: John Murray, 2002. ISBN 0-7195-5484-5.
 * Franks, Norman. Wings of Freedom: Twelve Battle of Britain Pilots. London: William Kimber, 1980. ISBN 0-7183-0197-8.
 * Galland, Adolf. The First and the Last: Germany's Fighter Force in WWII (Fortunes of War). South Miami, Florida: Cerberus Press, 2005. ISBN 1-84145-020-0.
 * Halpenny, Bruce Barrymore. Fight for the Sky: Stories of Wartime Fighter Pilots. Cambridge, UK: Patrick Stephens, 1986. ISBN 0-85059-749-8.
 * Halpenny, Bruce Barrymore. Fighter Pilots in World War II: True Stories of Frontline Air Combat (paperback). Barnsley, UK: Pen and Sword Books Ltd, 2004. ISBN 1-84415-065-8.
 * Orange, Vincent. Park: The Biography of Air Chief Marshal Sir Keith Park. London: Grub Street, 2001. ISBN 1-902304-61-6.

Aircraft

 * Ansell, Mark. Boulton Paul Defiant: Technical Details and History of the Famous British Night Fighter. Redbourn, Herts, UK: Mushroom Model Publications, 2005. pp. 712–714. ISBN 83-89450-19-4.
 * de Zeng, Henry L., Doug G. Stankey and Eddie J. Creek. Bomber Units of the Luftwaffe 1933–1945: A Reference Source, Volume 2. Hersham, Surrey, UK: Ian Allen Publishing, 2007. ISBN 978-1-903223-87-1.
 * Feist, Uwe. The Fighting Me 109. London: Arms and Armour Press, 1993. ISBN 1-85409-209-X.
 * Goss, Chris. Dornier 17: In Focus. Surrey, UK: Red Kite Books, 2005. ISBN 0-9546201-4-3.
 * Green, William. Famous Fighters of the Second World War. London: Macdonald, 1962.
 * Holmes, Tony. Hurricane Aces 1939–1940 (Aircraft of the Aces). Botley, Oxford, UK: Osprey Publishing, 1998. ISBN 1-85532-597-7.
 * Holmes, Tony. Spitfire vs Bf 109: Battle of Britain. Oxford, London: Osprey Publishing, 2007. ISBN 978-1-84603-190-8.
 * Huntley, Ian D. Fairey Battle, Aviation Guide 1. Bedford, UK: SAM Publications, 2004. ISBN 0-9533465-9-5.
 * Jones, Robert C. Camouflage and Markings Number 8: Boulton Paul Defiant, RAF Northern Europe 1936–45. London: Ducimus Book Limited, 1970.
 * Mason, Francis K. Hawker Aircraft since 1920. London: Putnam, 1991. ISBN 0-85177-839-9.
 * McKinstry, Leo. Hurricane: Victor of the Battle of Britain. London: John Murray Publishers, 2010. ISBN 1-84854-339-5
 * Molson, Kenneth M. et al. Canada's National Aviation Museum: Its History and Collections. Ottawa: National Aviation Museum, 1988. ISBN 978-0-660-12001-0.
 * Moyes, Philip, J.R. "The Fairey Battle." Aircraft in Profile, Volume 2 (nos. 25–48). Windsor, Berkshire, UK: Profile Publications, 1971. ISBN 0-85383-011-8
 * Parry, Simon W. Intruders over Britain: The Story of the Luftwaffe's Night Intruder Force, the Fernnachtjager. Washington, DC: Smithsonian Books, 1989. ISBN 0-904811-07-7.
 * Price, Alfred. Spitfire Mark I/II Aces 1939–41 (Aircraft of the Aces 12). London: Osprey Books, 1996, ISBN 1-85532-627-2.
 * Price, Alfred. The Spitfire Story: Revised second edition. Enderby, Leicester, UK: Silverdale Books, 2002. ISBN 1-85605-702-X.
 * Sarkar, Dilip. How the Spitfire Won the Battle of Britain. London: Amberly, 2011. ISBN 1-84868-868-7.
 * Scutts, Jerry. Messerschmitt Bf 109: The Operational Record. Sarasota, FL: Crestline Publishers, 1996. ISBN 978-0-7603-0262-0.
 * Ward, John. Hitler's Stuka Squadrons. London: Brown Reference, 2004. ISBN 0-7603-1991-X.
 * Warner, G. The Bristol Blenheim: A Complete History. London: Crécy Publishing, 2nd edition 2005. ISBN 0-85979-101-7.
 * Weal, John. Messerschmitt Bf 110 Zerstōrer Aces of World War 2. Botley, Oxford UK: Osprey Publishing, 1999. ISBN 1-85532-753-8.

Additional references

 * Books
 * Addison, Paul and Jeremy Crang. The Burning Blue: A New History of the Battle of Britain. London: Pimlico, 2000. ISBN 0-7126-6475-0.
 * Bergström, Christer. Barbarossa – The Air Battle: July–December 1941. London: Chervron/Ian Allen, 2007. ISBN 978-1-85780-270-2.
 * Bishop, Patrick. Fighter Boys: The Battle of Britain, 1940. New York: Viking, 2003 (hardcover, ISBN 0-670-03230-1); Penguin Books, 2004. ISBN 0-14-200466-9. As Fighter Boys: Saving Britain 1940. London: Harper Perennial, 2004. ISBN 0-00-653204-7.
 * Brittain, Vera. England's Hour. London: Continuum International Publishing Group, 2005 (paperback, ISBN 0-8264-8031-4); Obscure Press (paperback, ISBN 1-84664-834-3).
 * Campion, Garry. The Good Fight: Battle of Britain Wartime Propaganda and The Few. Basingstoke, Hampshire, UK: Palgrave Macmillan, 2010, First edition 2008. ISBN 978-0-23027-996-4.
 * Cooper, Matthew. The German Air Force 1933–1945: An Anatomy of Failure. New York: Jane's Publishing Incorporated, 1981. ISBN 0-531-03733-9.
 * Craig, Phil and Tim Clayton. Finest Hour: The Battle of Britain. New York: Simon & Schuster, 2000. ISBN 0-684-86930-6 (hardcover); 2006, ISBN 0-684-86931-4 (paperback).
 * Fiedler, Arkady. 303 Squadron: The Legendary Battle of Britain Fighter Squadron. Los Angeles: Aquila Polonica, 2010. ISBN 978-1-60772-004-1.
 * Fisher, David E. A Summer Bright and Terrible: Winston Churchill, Lord Dowding, Radar and the Impossible Triumph of the Battle of Britain. Emeryville, CA: Shoemaker & Hoard, 2005. ISBN 1-59376-047-7 (hardcover,); 2006, ISBN 1-59376-116-3 (paperback).
 * Foreman, John. Battle of Britain: The Forgotten Months, November And December 1940. Wythenshawe, Lancashire, UK: Crécy Publishing, 1989. ISBN 1-871187-02-8.
 * Gaskin, Margaret. Blitz: The Story of 29 December 1940. New York: Harcourt, 2006. ISBN 0-15-101404-3.
 * Haining, Peter. The Chianti Raiders: The Extraordinary Story of the Italian Air Force in the Battle of Britain. London: Robson Books, 2005. ISBN 1-86105-829-2.
 * Haining, Peter. Where the Eagle Landed: The Mystery of the German Invasion of Britain, 1940. London: Robson Books, 2004. ISBN 1-86105-750-4.
 * Halpenny, Bruce Barrymore. Action Stations: Military Airfields of Greater London v. 8. Cambridge, UK: Patrick Stephens, 1984. ISBN 0-85039-885-1.
 * Harding, Thomas. "It's baloney, say RAF aces". The Telegraph, 24 August 2006. Retrieved 3 March 2007.
 * Hough, Richard. The Battle of Britain: The Greatest Air Battle of World War II. New York: W.W. Norton, 1989. ISBN 0-393-02766-X (hardcover); 2005, ISBN 0-393-30734-4(paperback).
 * James, T.C.G. The Battle of Britain (Air Defence of Great Britain; vol. 2). London/New York: Frank Cass Publishers, 2000. ISBN 0-7146-5123-0(hardcover); ISBN 0-7146-8149-0 (paperback,).
 * James, T.C.G. Growth of Fighter Command, 1936–1940 (Air Defence of Great Britain; vol. 1). London; New York: Frank Cass Publishers, 2000. ISBN 0-7146-5118-4.
 * James, T.C.G. Night Air Defence During the Blitz. London/New York: Frank Cass Publishers, 2003. ISBN 0-7146-5166-4.
 * McGlashan, Kenneth B. with Owen P. Zupp. Down to Earth: A Fighter Pilot Recounts His Experiences of Dunkirk, the Battle of Britain, Dieppe, D-Day and Beyond. London: Grub Street Publishing, 2007. ISBN 1-904943-84-5.
 * March, Edgar J. British Destroyers; a History of Development 1892–1953. London: Seely Service & Co. Limited, 1966.
 * Olson, Lynne and Stanley Cloud. A Question of Honor: The Kościuszko Squadron: Forgotten Heroes of World War II. New York: Knopf, 2003. ISBN 0-375-41197-6. NB: This book is also published under the following title:
 * For Your Freedom and Ours: The Kościuszko Squadron – Forgotten Heroes of World War II.
 * Prien, Jochen and Peter Rodeike.Messerschmitt Bf 109 F,G, and K: An Illustrated Study. Atglen, Pennsylvania: Schiffer Publishing, 1995. ISBN 0-88740-424-3.
 * Ray, John. Battle of Britain. London: The Orion Publishing Co., 2003. ISBN 1-85409-345-2.
 * Ray, John Philip. The Battle of Britain: Dowding and the First Victory 1940. London: Cassel & Co., 2001. ISBN 0-304-35677-8.
 * Ray, John Philip. The Battle of Britain: New Perspectives: Behind the Scenes of the Great Air War. London: Arms & Armour Press, 1994 (hardcover, ISBN 1-85409-229-4); London: Orion Publishing, 1996 (paperback, ISBN 1-85409-345-2).
 * Rongers, Eppo H. De oorlog in mei '40, Utrecht/Antwerpen: Uitgeverij Het Spectrum N.V., 1969, No ISBN.
 * Townsend, Peter. Duel of Eagles (new edition). London: Phoenix, 2000. ISBN 1-84212-211-8.
 * Wellum, Geoffrey. First Light: The Story of the Boy Who Became a Man in the War-Torn Skies Above Britain. New York: Viking Books, 2002. ISBN 0-670-91248-4 (hardcover); Hoboken, NJ: Wiley & Sons, 2003. ISBN 0-471-42627-X (hardcover); London: Penguin Books, 2003. ISBN 0-14-100814-8 (paperback).
 * Zaloga, Steven J. and Richard Hook. The Polish Army 1939–45. London: Osprey, 1982. ISBN 0-85045-417-4.