56 Anti-Aircraft Brigade was formed in September 1939 as a “Light” Brigade at Uxbridge, London and later moved to Chelmsford, Essex. It deployed as part of 6 Anti-Aircraft Brigade at Uxbridge. When the divisions were abolished in Oct 1942, it became part of 2 Anti-Aircraft Group and later 1 Anti-Aircraft Group.
56 Anti-Aircraft Brigade went into suspended animation in June 1945.
Illustrations of the formation badges under which a unit served or supported are given. This is no guarantee that the unit used this formations badge.
| Sep 39 | Uxbridge |  | 6 Anti-Aircraft Division |
| 1940 | Chelmsford | | 6 Anti-Aircraft Division |
| Oct 42 | London |  | 2 Anti-Aircraft Group |
| Oct 44 | London | | 1 Anti-Aircraft Group |
Order of Battle 1939
| 11 (City of London Yeomanry) Light Anti-Aircraft Regiment |
| 12 (Finsbury Rifles) Light Anti-Aircraft Regiment |
| 16 Light Anti-Aircraft Regiment |
| 17 Light Anti-Aircraft Regiment |
Order of Battle 1940-41
| 16 Light Anti-Aircraft Regiment |
| 29 (Kent) Searchlight Regiment |
| 73 (Kent Fortress) Searchlight Regiment |
Order of Battle 1941-42
| 4 Light Anti-Aircraft Regiment – Joined Spring 42 |
| 69 Light Anti-Aircraft Regiment – Joined Jan, left Feb 42 |
| 86 Light Anti-Aircraft Regiment – Joined Jan, left Apr 42 |
| 50 Light Anti-Aircraft Regiment – Joined Mar 42 |
| 29 Searchlight Regiment – Left Jan 42 |
| 73 Searchlight Regiment |
| 6 Anti-Aircraft Z Regiment – Left Summer 41 |
| 12 Anti-Aircraft Z Regiment – Joined Mar 41, left Jan 42 |
Order of Battle May 1942
| 84 Heavy Anti-Aircraft Regiment – Joined Aug, left Sep 42 |
| 101 Heavy Anti-Aircraft Regiment – Joined Jun, left Jul 42 |
| 4 Light Anti-Aircraft Regiment |
| 66 Light Anti-Aircraft Regiment – Joined Jun 42, to 71 Anti-Aircraft Brigade same month |
| 28 Searchlight Regiment – Joined Jun 42 |
| 32 Searchlight Regiment – Joined Aug 42 |
| 73 Searchlight Regiment |
