45 Light Anti-Aircraft Regiment RA(TA) was formed in July 1940. It was converted to 45 Garrison Regiment RA in November 1944. It re-organised as 603 Infantry Regiment RA in February 1945 and disbanded in December 1945.
| Jul 40 | Formed | |
| Jul 40 | 1 Anti-Aircraft Brigade, 11 Anti-Aircraft Division | Crewe, Cheshire, UK |
| Nov 42 | 5 Corps | Bougie, Algeria |
| Jan 43 | 1 Army | N Africa |
| May 43 | 52 Anti-Aircraft Brigade | Tunis, Tunisia |
| Sep 43 | 8 Army | Italy |
| Apr 44 | 66 Anti-Aircraft Brigade | Italy |
| Jun 44 | 66 Anti-Aircraft Brigade | Salerno, Italy |
| Nov 44 | Became 45 Garrison Regiment RA | Italy |
Batteries
| Jul 40 | 102 |
| Sep 41 | 265, 306 |
| Dec 41 | 265 |
| Jul 42 | 135, 142, 265 |
