131 (Mixed) Heavy Anti-Aircraft Regiment RA(TA) was formed at Bitterne in August 1941. The Regiment was disbanded August 1943.
| Aug 41 | Formed | Bitterne, Hampshire, UK |
| Aug 41 | 35 Anti-Aircraft Brigade, 5 Anti-Aircraft Division | Southampton, Hampshire, UK |
| Jul 42 | 37 Anti-Aircraft Brigade, 6 Anti-Aircraft Division | Essex, UK |
| Aug 42 | 70 Anti-Aircraft Brigade, 4 Anti-Aircraft Division | North West England |
| Oct 42 | 70 Anti-Aircraft Brigade, 4 Anti-Aircraft Group | North West England |
| Mar 43 | 53 Anti-Aircraft Brigade, 4 Anti-Aircraft Group | 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 |
