The unit was formed as 31 Field Brigade (Army) RA in March 1936 by conversion of 3 Light Brigade RA. 31 Field Regiment RA was re-designated from 31 Field Brigade (Army) RA in September 1938 on a two battery basis. In January 1942 it was re-organised as RHQ and one battery until October that year when it had three batteries. Post war, 31 Field Regiment RA was converted to 31 Light Anti-Aircraft Regiment RA in November 1946.
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.
| Sep 39 |  |
GHQ Middle East Forces Attached from RA Group Middle East |
Mersa Matruh, Egypt |
| Sep 39 |  |
7 Infantry Division | Egypt |
| Oct 39 | HQ RA Group | Mersa Matruh, Egypt | |
| Jun 40 |  |
4 Indian Division | Baggush, Egypt |
| Dec 40 | |
4 Indian Division | Sudan |
| Jan 41 | |
4 Indian Division | Keren, Eritrea |
| Mar 41 | |
4 Indian Division | Sudan |
| May 41 | |
4 Indian Division | Palestine |
| Jun 41 | |
4 Indian Division | Syria |
| Jul 41 | |
4 Indian Division | N Africa |
| May 42 | |
4 Indian Division | Palestine |
| Jun 42 | |
4 Indian Division | N Africa |
| Dec 43 | |
4 Indian Division | Taranto, Italy |
| Nov 44 | |
4 Indian Division | Greece |
Batteries
| Mar 36 | 116, 118, 119 |
| Sep 38 | 105/119, 116/118 |
| Dec 41 | 118 suspended animation, remainder combined as 116/105 Bty |
| Feb 42 | 105/119, 116/118 |
| Oct 42 | 105, 116, 118/119 |
Equipment
| Jul 41 | 24 x 25 pdr Guns |