55 Anti-Aircraft Brigade was raised in September 1939 at Exeter as a Light AA Brigade. It was assigned to 5 Anti-Aircraft Division. In 1940 it moved to 8 AA Division and became a standard AA Division, dropping the “Light” from its title. When the divisions were abolished in 1942 it came under 3 AA Group. 55 Anti-Aircraft Brigade was converted to the HQ of 306 Infantry Brigade in January 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 | Exeter |  | 5 Anti-Aircraft Division |
| Nov 40 | Bristol |  | 8 Anti-Aircraft Division |
| Oct 42 | Bristol |  | 3 Anti-Aircraft Group |
| Jan 45 | Converted to HQ 306 Infantry Brigade | | |
Order of Battle 1939
| 23 Light Anti-Aircraft Regiment |
| 24 Light Anti-Aircraft Regiment |
| 34 Light Anti-Aircraft Regiment |
| 35 Light Anti-Aircraft Regiment |
| 36 Light Anti-Aircraft Regiment |
Order of Battle 1940
| 56 (Cornwall) Heavy Anti-Aircraft Regiment |
| 118 Heavy Anti-Aircraft Regiment (part) – Left May 41 |
| 58 (Argyll and Sutherland Highlanders) Light Anti-Aircraft Regiment (part) – Left May 41 |
| 81 Searchlight Regiment – Joined Nov 40 |
| 82 Searchlight Regiment – Joined Nov 40 |
Order of Battle 1941-42
| 56 Heavy Anti-Aircraft Regiment– Left Dec 41 |
| 79 (Hertfordshire Yeomanry) Heavy Anti-Aircraft Regiment – Joined Jul 42 |
| 103 Heavy Anti-Aircraft Regiment – Joined May 42 |
| 116 Heavy Anti-Aircraft Regiment – Joined Dec 41 |
| 162 (Mixed) Heavy Anti-Aircraft Regiment – Joined Jun 42 |
| 166 (Mixed) Heavy Anti-Aircraft Regiment – Joined Aug 42 |
| 36 Light Anti-Aircraft Regiment – Joined Dec 41, Left Apr 42 |
| 44 Light Anti-Aircraft Regiment – Joined Jan 42, Left Mar 42 |
| 46 Light Anti-Aircraft Regiment – Joined May 41 |
| 55 (Devonshire) Light Anti-Aircraft Regiment – Joined Apr 42 |
| 137 Light Anti-Aircraft Regiment – Joined Feb 42 |
| 29 (Kent) Searchlight Regiment– Joined Jan, left Jun 42 |
| 81 Searchlight Regiment – Left Mar 42 |
| 82 Searchlight Regiment – Left Dec 41 |
| 85 Searchlight Regiment – Joined Dec 41, left Mar 42 |
| 9 Anti-Aircraft Z Regiment – Joined Dec 41 |
