131 (Mixed) Heavy Anti-Aircraft Regiment RA (TA) was formed at Bitterne in August 1941. The Regiment served in Anti-Aircraft Command for the two years it existed. 131 (Mixed) Heavy Anti-Aircraft Regiment RA (TA) was disbanded August 1943.
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.
| Aug 41 | Formed | Bitterne, Hampshire, UK | |
| Aug 41 |  |
5 Anti-Aircraft Division, 35 Anti-Aircraft Brigade | Southampton, Hampshire, UK |
| Jul 42 |  |
6 Anti-Aircraft Division, 37 Anti-Aircraft Brigade | Essex, UK |
| Aug 42 |  |
4 Anti-Aircraft Division, 70 Anti-Aircraft Brigade | North West England |
| Oct 42 |  |
4 Anti-Aircraft Group, 70 Anti-Aircraft Brigade | North West England |
| Mar 43 | |
4 Anti-Aircraft Group, 53 Anti-Aircraft Brigade | North West England |
| Aug 43 | Disbanded |
Batteries
| Aug 41 | 251 (Buckinghamshire), 310 (Mixed), 368 (Mixed) |
| Oct 41 | 310 (Mixed), 368 (Mixed), 458 |
| Dec 41 | 310 (Mixed), 368 (Mixed), 428, 458 |
| Apr 42 | 310, 368, 428 |
| Jul 42 | 310, 368, 376, 428 |