AA Command had been created in 1938 to control the Territorial Army's rapidly-expanding anti-aircraft organisation within Air Defence of Great Britain. On the outbreak of war in September 1939, it commanded seven AA Divisions, each with several AA Brigades, disposed around the United Kingdom. Continued expansion made this organisation unwieldy, so in November 1940 – during the Luftwaffe's nightly Blitz on London and other British cities – five further AA Divisions were organised, and all the divisions grouped under three corps headquarters directly subordinate to AA Command. II AA Corps covered the Midlands and NorthWest of England and North Wales, and by February 1941 comprised four AA divisions and 14 brigades. Its boundaries roughly coincided with No. 9 Group RAF and No. 12 Group RAF of RAF Fighter Command.
Order of battle
II AA Corps had the following organisation from February 1941: Corps HQ: Hucknall, Nottinghamshire General Officer Commanding: Lieutenant-General M. F. Grove-White
2nd AA Division">2nd Anti-Aircraft Division (United Kingdom)">2nd AA Division
As soon as it was organised, II AA Corps had to deal with the 1940–41 Blitz on industrial cities and towns such as Barrow-in-Furness, Birmingham, Coventry, Derby, Hull, Leeds, Liverpool, Manchester, Nottingham and Sheffield. The corps was responsible for large Gun Defence Areas around Merseyside, Humberside and South Yorkshire, and the North and West Midlands, with 'Indicator Belts' and 'Killer Belts' of searchlights in between, the former working with the GDAs and RAF Sectors, the latter with the night fighters in the air. Redeployment was called for in 1942 when the Luftwaffe began the 'Baedeker raids' on towns and cities such as Norwich, King's Lynn and York that had previously warranted little AA defence.
Disbandment
The AA Corps and Divisional HQs were disbanded in October 1942 and a replaced by a more flexible system of AA Groups, each aligned with a Group of RAF Fighter Command. The area covered by II AA Corps became the responsibility of two of the new groups: 4th AA Group with 9 Group RAF, and 5th AA Group with 12 Group RAF.
