2 Heavy Anti-Aircraft Regiment RA was re-designated as 2 Anti-Aircraft Regiment RA from 2 Anti-Aircraft Brigade RA in May 1938. It was re-designated as Heavy Anti-Aircraft in June 1940. In April 1947 it became 21 Heavy Anti-Aircraft Regiment RA.
| May 38 | 3 Anti-Aircraft Brigade | Lichfield, Staffordshire, UK |
| Nov 39 | 2 Anti-Aircraft Brigade | Boulogne, France |
| May 40 | Home Forces | Aberporth, Dyfed, UK |
| Sep 40 | British Troops Egypt | Mersa Matruh, Egypt |
| Feb 41 | 1 Australian Corps | Piraeus, Greece |
| May 41 | British Troops Egypt | Alexandria, Egypt |
| Aug 41 | British Troops Egypt | N Africa |
| Jan 43 | Diluted with African Pioneer Corps men | |
| Mar 43 | 8 Army | Benghazi, Libya |
| May 43 | 21 Anti-Aircraft Brigade | Suez Canal, Egypt |
| Jul 43 | 8 Army | Port Said, Egypt |
| Sep 43 | Palestine |
Batteries
| May 38 | 4, 5, 6, 2 LAA |
| Sep 40 | 16, 20, 27 – 27 Battery left for Malta on the 27th September |
| Apr 41 | 16, 20 |
| Aug 41 | 20, 199 |
| Feb 43 | 16, 20, 28 |
