1st Anti-Aircraft Group (1 AA Group) was a formation created by the British Army's Anti-Aircraft Command in 1942 to control anti-aircraft (AA) units defending London against Luftwaffe attacks during World War II. It continued this role into the Cold War until disbandment in 1955.
World War II
1 AA Group was formed on 1 October 1942 when Lieutenant-General Sir Frederick 'Tim' Pile, Commander-in-Chief of Anti-Aircraft Command (AA Command), scrapped its previous conventional structure of Corps and Divisions. Each of the new AA Groups was commanded by a major-general and controlled a number of AA Brigades and support units. The new group boundaries were aligned with the Fighter Groups of the Royal Air Force (RAF). (It was jokingly observed that a reorganisation that eliminated eight general officers was the best contribution to the war effort at the time!)
1 AA Group's area of responsibility covered the London Inner Artillery Zone (IAZ) formerly controlled by 1 AA Division, and later included the 'Thames North' and 'Thames South' defences either side of the Thames Estuary from the former 6 AA Division. This tightly defined area was almost surrounded by 2 AA Group covering South East England, and together the two groups mirrored No. 11 Group RAF.
The first General Officer Commanding (GOC) of 1 AA Group was Maj-Gen Erroll Tremlett, who had previously commanded 10 AA Division. A former first-class cricketer, Tremlett had distinguished himself earlier in the war when he commanded 54th (Argyll and Sutherland Highlanders) Light Anti-Aircraft Regiment, Royal Artillery defending the mole during the Dunkirk evacuation.
Order of Battle 1943–44
When they were first established there was much interchange of the units allocated to 1 and 2 AA Groups, but from early 1943 1 AA Group had the following order of battle (temporary attachments omitted): 26 (London) AA Brigade 111 Heavy AA (HAA) Regiment, Royal Artillery (RA) – to 21st Army Group by August 1943 132 (Mixed) HAA Regiment, RA – to 2 AA Gp July 1944 137 (Mixed) HAA Regiment, RA 156 (Mixed) HAA Regiment, RA 48 AA Brigade 117 HAA Regiment, RA – from Orkney and Shetland Defences (OSDEF) October 1943; to 2 AA Gp May 1944 141 (Mixed) HAA Regiment, RA – to 7 AA Gp December 1943 155 (Mixed) HAA Regiment, RA 160 (Mixed) HAA Regiment, RA – from 2 AA Gp by March 1944 163 (Mixed) HAA Regiment, RA 164 (Mixed) HAA Regiment, RA – left October 1943
49 AA Brigade
141 Light AA (LAA) Regiment, RA – to Gibraltar August 1943
26 (London Electrical Engineers) (Mixed) Searchlight (S/L) Regiment, RA
80 S/L Regiment, RA – from 4 AA Gp by April 1944
1 (Mixed) AA 'Z' Regiment, RA
6 AA 'Z' Regiment, RA – to 37 AA Bde August 1943
14 AA 'Z' Regiment, RA – to 4 AA Gp April 1943
19 (Mixed) AA 'Z' Regiment, RA
301 Gun Operations Room (GOR), Stanmore
601 GOR, Brompton Road
1 AA Group School, Chelmsford
1 AA Group (Mixed) Practice Camp
1 AA Group Mixed Signal Unit, Royal Corps of Signals (RCS), Uxbridge
1 Mixed Signal Company
1 AA Command Mixed Signal Office Section (under AA Command) 1 AA Group Mixed Signal Office Section 26 AA Bde Mixed Signal Office Section 48 AA Bde Mixed Signal Office Section 49 AA Bde Mixed Signal Office Section 4 AA Line Maintenance Section 2 Mixed Signal Company 301 GOR Mixed Signal Section 601 GOR Mixed Signal Section 5 AA Line Maintenance Section HQ 1 AA Group Royal Army Service Corps (RASC) 900, 902, 907 AA (M) Transport Companies 919, 921 AA (M) Transport Companies – joined November 1943 1 AA Group Royal Army Medical Corps (RAMC) Company 1 AA Group Royal Army Ordnance Corps (RAOC) 10 AA Workshop Battalion, Royal Electrical and Mechanical Engineers (REME) 1, 6 AA Workshop Companies 1 AA Group Radio Maintenance Company – later divided into 101 and 102 Radio Maintenance Detachments; joined by 105 Detachment June 1944
'Mixed' indicates that women of the Auxiliary Territorial Service (ATS) were integrated into the unit. HAA regiments were equipped with 3.7-inch guns, LAA regiments with Bofors 40 mm guns, 'Z' Regiments with Z Battery rocket projectors, and S/L regiments with a variety of searchlights and Light machine guns.
By August 1943 the Group had taken over control of two further AA brigades, with the associated signal units: