It defended the Midlands and North West of England and Wales during the Blitz and the middle years of the Second World War.

[2][3][4][5] 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.

[2][5][6][7] II AA Corps had the following organisation from February 1941:[8][9][10][11][12][13] Corps HQ: Hucknall, Nottinghamshire General Officer Commanding: Lieutenant-General M. F. Grove-White[5][14][15] 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 (GDAs) 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.