51st (London) Heavy Anti-Aircraft Regiment, Royal Artillery

51st (London) Heavy Anti-Aircraft Regiment was a volunteer air defence unit of Britain's Territorial Army from 1922 until 1955. During World War II it served in Norway, The Blitz, North Africa (when detachments defended Crete and Tobruk), and finally in Italy until the end of the war in Europe, by which time a proportion of the regiment's personnel were African soldiers, and the guns were engaging ground targets rather than aircraft.

Origin
German air raids by Zeppelin airships and Gotha bombers on London and other British cities during World War I had shown the need for strong anti-aircraft (AA) defences in any future war. When the Territorial Army (TA) was reformed in 1922 it included a number of dedicated AA units. The senior of these was 51st (London) Anti-Aircraft Brigade, Royal Garrison Artillery, (TA), formed at the Duke of York's Headquarters in Chelsea, London with 151st, 152nd and 153rd (London) AA Batteries. It formed part of 26th (London) Air Defence Brigade also headquartered at the Duke of York's Headquarters.

As Britain's AA defences expanded during the 1930s, higher formations became necessary, and the 26th AD Bde (now renamed 26th (London) AA Group), including 51st AA Bde, was assigned to  1st AA Division organised to cover London and the Home Counties. The Royal Garrison Artillery had been absorbed into the Royal Artillery (RA) in 1924; in 1938 the RA replaced its traditional unit designation 'Brigade' by the modern 'Regiment', and the 'AA Groups' reverted to the more usual formation title of 'Brigades'. Anti-Aircraft Command was formed in April 1939 to control all the TA's AA units and formations.

World War II
When AA Command mobilised on 28 August 1939, 51 AA Regiment was assigned to a newly formed 49 AA Bde in London, still within 1 AA Division.

Norway
In April 1940, 51 AA Regiment went to Norway in 6 AA Bde as part of the North-Western Expeditionary Force sent to capture Narvik. German aircraft were active in the area and the AA guns claimed a number of aircraft destroyed. After the collapse of the Norwegian Campaign, the force from Narvik was the last part of the British expedition to be evacuated. Although much of the force's equipment was saved, the AA guns were kept in action until the last minute to cover the evacuation, and many had to be abandoned when the last troopship left on 8 June.

The Blitz
In the summer of 1940, along with other AA units equipped with 3-inch or the newer 3.7-inch AA guns guns, the 51st was designated a Heavy AA Regiment. During the Battle of Britain and the early part of The Blitz it served in 48 AA Bde responsible for the air defence of London.

North Africa
The regiment left the UK again in late 1940 and arrived in Egypt in January 1941. 151 Battery was sent on to Crete, while RHQ, 152 and 153 Batteries served in the Western Desert and Libya under British Troops Egypt.

Crete
When the German invasion of Crete began in May 1941, 151 (London) Battery from 51 HAA Regiment was stationed to defend the Suda-Canea area with one troop of six 3.7-inch guns. After a bad start, the Germans succeeded in taking the whole island, and many of the defenders could not be evacuated and became prisoners of war.

Tobruk
51 HAA Regiment also contributed to the epic Defence of Tobruk in 1941, 153 (London) Battery serving under 4 AA Bde throughout the 240-day long siege. The Official History records that the AA artillery was 'incessantly in action against attacks of all kinds, from all heights, but especially by dive-bombers'.

Once Tobruk was relieved, 51 HAA Regiment was withdrawn to Palestine and became part of Ninth Army. The regiment returned to the Desert under Eighth Army late in 1942 for the advance across North Africa after the Second Battle of El Alamein.

Italy
The regiment remained under Middle East Forces during the Allied invasion of Sicily, but it rejoined Eighth Army for the Italian Campaign from September 1943 until the end of the war in Europe.

By August 1944 the regiment was serving in 2 AA Bde in Eighth Army. The brigade made a long march from Ancona to Anzio that month, but 51 HAA was then left behind to absorb African Other Ranks, who were replacing a proportion of the British personnel in a process known at the time as 'dilution'.

After training at Anzio, the regiment resumed its place in the brigade in October 1944. Due to the decline of the Luftwaffe, there was little air activity, and from Autumn 1944 the Heavy AA guns were more often used as medium artillery, engaging enemy ground positions with their 3.7-inch High Explosive ammunition. These were mainly HF (harassing fire), CB (counter-battery) and CM (counter-mortar) shoots. The HAA units in this brigade also developed a technique known as 'Honey Combing': firing accurate air bursts over enemy AA positions to suppress them and enable Allied aircraft to operate safely in the area.

For this work the AA units were subdivided to support infantry formations. For example, in November 1944, 51 HAA had two batteries providing AA defence for Arezzo, and one operating in the field role with British XIII Corps in US Fifth Army. At New Year 1945 one battery was still defending the Arezzo rail head while the other two were in the AA/Field role supporting 6th Armoured Division (two troops), 1st Division (one troop) and 78th Division (one troop).

In January 1945, XIII Corps reverted to Eighth Army command. In April 51 HAA took part in the Spring 1945 offensive in Italy, frequently supporting the Friuli Combat Group and Folgore Combat Group of the Italian Co-Belligerent Army operating in XIII Corps. As well as supporting these attacks, the regiment fired various tasks, including CM and bridge demolition, and against infantry formations, but found that the speed of the enemy withdrawal made it difficult to stay in range, and frequent moves forward were required. The regiment was in the Forli area when the German forces in Italy signed the instrument of surrender on 29 April.

Postwar


The regiment was reconstituted in the TA in 1947 as 451 HAA Regiment (London) at the Duke of York's HQ in 64 AA Bde. In 1952 it was adopted by the Metropolitan Borough of Chelsea and was renamed 451 (Chelsea) HAA Regiment, but it was disbanded in 1955 when AA Command was abolished.

Honorary Colonel
Major Lionel Tennyson, 3rd Baron Tennyson, the former England cricket captain, was appointed Honorary Colonel of the regiment on 9 August 1931 and held the position until 1947.

Memorial
There is a memorial plaque to 51 HAA Regiment in St Luke's Church, Chelsea, carrying 96 names of men who died on service during World War II.

External Sources

 * British Army units from 1945 on
 * British & Commonwealth Orders of Battle
 * British Military History
 * Military History Network
 * Orders of Battle at Patriot Files
 * Rats of Tobruk Association of Victoria
 * The Royal Artillery 1939–45
 * UK National Inventory of War Memorials