31 Light Anti-Aircraft Regiment RA (TA) was formed at Perth, in August 1939. It moved to Sicily in July 1943 and then to Italy in the September. It went into suspended animation in November 1945. 31 Light Anti-Aircraft Regiment RA (TA) was re-constituted as 531 Light Anti-Aircraft/Searchlight Regiment RA (TA) in January 1947.
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 39 |  |
Scottish Command | Perth, Perthshire, UK |
| Jul 43 |  |
8 Army | Sicily |
| Sep 43 | |
8 Army | Italy |
| Nov 45 | Suspended animation |
Batteries
| Sep 39 | 61, 101 |
| Mar 41 | 61, 101, 224 |
| Feb 42 | 61, 101, 224, 447 |
| Jul 42 | 61, 101, 224 |