4th Anti-Aircraft Division (United Kingdom)

The 4th Anti-Aircraft Division (4 AA Division) was an air defence formation of Britain's Territorial Army, created in the period of tension before the outbreak of World War II. It defended North West England during the Blitz.

Origin
Increasing concern during the 1930s about the threat of air attack led to large numbers of units of the part-time Territorial Army (TA) being converted to anti-aircraft (AA) gun and searchlight roles in the Royal Artillery (RA) and Royal Engineers (RE), and higher formations became necessary to control them. One such formation was 4 AA Division, raised on 1 September 1938 in Western Command, with its Headquarters at Chester. The first General Officer Commanding (GOC) was Maj-Gen Hugh Martin.

The AA Divisions were unlike field formations: they were established to organise training and later exercise operational command in the static conditions of home defence, but relied entirely on the Home Forces commands for logistic support, supplies, and heavy repairs. They came under the operational control of RAF Fighter Command.

4 AA Division was initially responsible for the industrial areas of the North West and West Midlands of England and North and South Wales. At first it consisted of two brigades: the existing Liverpool-based 33rd (Western) AA Bde transferred from 2 AA Division and the newly formed 34th (South Midland) AA Bde based at Coventry. Shortly afterwards, 44th AA Bde was formed at Manchester. The division came under the control of Anti-Aircraft Command when that was formed in April 1939.

Mobilisation
The deterioration in international relations led to a partial mobilisation in June 1939, and a proportion of TA AA units manned their war stations under a rotation system known as 'Couverture'. Full mobilisation of AA Command came in August 1939, ahead of the declaration of war on 3 September 1939. Two new brigades, 53rd (Light) AA Bde composed of Light AA (LAA) units, and 54th, composed of searchlight units, were in the process of formation in 4 AA Division as mobilisation proceeded.

Order of Battle
On mobilisation in August 1939, the division was composed as follows:
 * 33rd (Western) Anti-Aircraft Brigade – HQ at Liverpool
 * 70th (3rd West Lancashire) AA Regiment, RA – Heavy Anti-Aircraft (HAA) unit formed in 1937 at Aigburth, Liverpool, by conversion of 89th (3rd West Lancashire) Field Brigade, RA
 * 81st AA Regiment, RA – HAA unit formed in 1936 at Stalybridge and Stockport by conversion of 60th (Cheshire & Shropshire) Medium Brigade, RA
 * 93rd AA Regiment, RA – new HAA unit raised in 1939 in Birkenhead and Chester
 * 38th (The King's Regiment) AA Battalion, RE – Searchlight unit formed in 1936 at Liverpool by conversion of 6th (Rifles) Bn King's Regiment (Liverpool)
 * 4th Battalion, The Loyal Regiment (North Lancashire) (62nd Searchlight Regiment, RA) – infantry battalion based at Preston converted into a searchlight unit in 1938
 * 33rd AA Brigade Company Royal Army Service Corps
 * 34th (South Midland) Anti-Aircraft Brigade – HQ at Coventry
 * 69th (Royal Warwickshire Regiment) AA Regiment, RA – HAA unit formed at Birmingham in 1936 by conversion of 6th Battalion Royal Warwickshire Regiment
 * 73rd AA Regiment, RA – HAA unit raised at Wolverhampton and West Bromwich in 1938 from batteries drawn from 62nd (North Midland) Field Brigade, RA and 51st (Midland) Medium Brigade, RA
 * 95th (Birmingham) AA Regiment, RA – newly raised in April 1939, with one battery from 73 AA Regiment
 * 34th AA Brigade Company, RASC
 * 44th Anti-Aircraft Brigade – HQ at Manchester
 * 65th (The Manchester Regiment) AA Regiment, RA – HAA unit formed at Hulme in 1936 by conversion of 6th/7th Battalion Manchester Regiment
 * 39th (The Lancashire Fusiliers) AA Battalion, RE – Searchlight unit formed at Salford in 1936 by conversion of 7th Bn Lancashire Fusiliers
 * 71st (East Lancashire) Searchlight Regiment, RA – new searchlight unit raised in Manchester in 1938
 * 44th AA Brigade Company, RASC
 * 53rd Light Anti-Aircraft Brigade – Forming at Chester
 * 15th (Isle of Man) LAA Regiment, RA – at Douglas, Isle of Man
 * 21st LAA Regiment, RA – at Liverpool
 * 25th LAA Regiment, RA – at Liverpool
 * 33rd LAA Regiment, RA – at Liverpool
 * 53rd AA Brigade Company, RASC
 * 54th Anti-Aircraft Brigade – forming at Sutton Coldfield
 * 41st (5th North Staffordshire Regiment) AA Battalion, RE – infantry battalion at Stoke-on-Trent converted to searchlights in 1936
 * 45th (The Royal Warwickshire Regiment) AA Battalion, RE – infantry battalion at Birmingham converted to searchlights in 1936
 * 59th (Warwickshire) Searchlight Regiment, RA – new unit formed from a battery of 45 AA Bn in 1938
 * 61st (South Lancashire Regiment) Searchlight Regiment, RA – infantry battalion at St Helens converted to searchlights in 1938
 * 54th AA Brigade Company, RASC
 * 4th AA Divisional Signals, Royal Corps of Signals – formed at Chester out of 55th (West Lancashire) Divisional Signals
 * 4th AA Divisional Workshop, Royal Army Ordnance Corps

Deployment
At this point the division had a strength of 92 HAA guns (3-inch, 3.7-inch and 4.5-inch) while in the LAA role there were 26 3-inch, 13 2-pounder 'pom-pom' and 40 mm Bofors guns, and 469 light machine guns (LMGs), together with 244 searchlights. The HAA guns were deployed in the defended areas as follows:


 * Liverpool	– 19 (plus 3 out of action)
 * Manchester	– 12 (plus 10 out of action)
 * Birmingham	– 20 (plus 4 out of action)
 * Coventry	–12
 * Cardiff	– 6 (plus 2 out of action)
 * Newport	– 4

Phoney War
During the period of the Phoney War, the AA defences of NW England were not tested in action, and the time was spent in equipping and training the TA units. AA Command also had to provide equipment and units to the British Expeditionary Force assembling in France. From 4 AA Division, 73rd AA Regiment went to France in November 1939 where it joined 12th Anti-Aircraft Brigade providing AA cover for the airfields of the RAF's Advanced Air Striking Force. In January 1940, Maj-Gen Martin went to command the AA defences of the BEF. He was replaced by Maj-Gen Charles Cadell, recently returned from commanding the AA defences of Malaya.

Battle of Britain
In the summer of 1940, all AA units equipped with 3-inch or heavier guns were designated as Heavy AA (HAA) regiments to distinguish them from the newer LAA units. Also, in August the AA battalions were transferred from the RE to the RA, which designated them searchlight regiments.

Deployment
At the start of the Battle of Britain, in July 1940, 4 AA Division's guns were deployed as follows:
 * Liverpool	– 52
 * Manchester – 20
 * Crewe	– 8
 * Birmingham	– 64
 * Coventry	– 44
 * RAF Ringway – 4
 * Vital Points – 52 (mainly LAA)

Reorganisation
In September 1940, 4 AA Division formed 4th AA Z Regiment to command the new short-range rocket weapons known as Z Batteries. Also in September 1940, RAF Fighter Command created a new HQ (No. 9 Group RAF) to cover NW England, and henceforth 4 AA Division cooperated with it.

As the Battle of Britain fought over southern England in the summer of 1940 developed into the night bombing of the Blitz in the autumn, AA Command continued to expand. In November a new division was formed by splitting 34 and 54 AA Brigades off from 4 AA Division to create 11 AA Division, which took over responsibility for the West Midlands, while 9 AA Division took over South Wales. At the same time, 4 AA Division came under the control of a newly formed II AA Corps.

The Blitz
The cities of NW England were heavily bombed during the winter of 1940–41 (the Liverpool Blitz and Manchester Blitz) and 'the actions fought [by the AA batteries] were as violent, dangerous and prolonged as any in the field'. 'On an HAA 4.5-inch position of 44th AA Brigade in Manchester, the power rammer on one gun failed. One Gunner loaded 127 of the 86-lb [40 kg] rounds himself in eleven hours of action, despite injuries to his fingers'.

The wide Mersey Estuary left a gap in the Liverpool defences that could not be fully covered by AA guns, and by mid-1941 AA Command had begun constructing three Maunsell Forts in the estuary on which to mount AA guns.

Order of Battle
During the winter of 1940–41, the division was composed as follows:


 * 33 AA Brigade – Liverpool
 * 103 HAA Regiment, RA – formed May 1940
 * 106 HAA Regiment, RA – formed August 1940
 * 33 LAA Regiment, RA – as above
 * 42 LAA Regiment, RA – formed November 1939
 * 65 LAA Regiment, RA (part) – formed November 1940
 * 44 AA Brigade – Manchester
 * 98 HAA Regiment, RA – formed 1939
 * 115 HAA Regiment, R – formed November 1940
 * 54 (Argyll & Sutherland Highlanders) LAA Regiment, RA – formed 1938 by conversion of 9th (Dumbartonshire) Bn, Argyll and Sutherland Highlanders
 * 76 LAA Regiment, RA – formed February 1941
 * 53 AA Brigade – North Midlands
 * 39 (Lancashire Fusiliers) S/L Regiment, RA – as above
 * 62 (The Loyals) S/L Regiment, RA – as above
 * 71 (East Lancashire) S/L Regiment, RA – as above
 * 92 S/L Regiment, RA – formed May 1941
 * 4 AA Z Regiment, RA – as above
 * 13 AA Z Regiment, RA – 'formed August 1941

Disbandment
At the end of September 1942, AA Command disbanded the AA Corps and Divisions and replaced them with new AA Groups, whose areas of responsibility coincided with the Groups of RAF Fighter Command. 4 AA Division's responsibilities were taken over by 4 AA Group, with its HQ at Preston, which covered NW England and N Wales and operated with 9 Group RAF. 4 AA Divisional Signals became 4 AA Group Signals on 21 October 1942 4 AA Group in turn was disbanded in November 1944.

External sources

 * British Generals of WWII at Generals.dk.
 * British Military History
 * Orders of Battle at Patriot Files
 * The Royal Artillery 1939–45