42 Light Anti-Aircraft Regiment RA (TA) was formed at Waltham Abbey in November 1939. The Regiment moved to North Africa in December 1941. It fought in North Africa and Italy until the end of the war. 42 Light Anti-Aircraft Regiment RA (TA) was disbanded in January 1945.
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.
| Nov 39 | Formed from batteries from 17 & 36 Light Anti-Aircraft Regiments |
Waltham Abbey, Essex, UK | |
| Nov 39 |  |
4 Anti-Aircraft Division, 34 Anti-Aircraft Brigade | South Midlands, UK |
| May 41 |  |
1 Anti-Aircraft Division, 49 Anti-Aircraft Brigade | London, UK |
| Dec 41 |  |
Middle East Forces | N Africa |
| Sep 42 |  |
1 Armoured Division | N Africa |
| May 44 | |
1 Armoured Division | Italy |
| Oct 44 |  |
8 Army | Italy |
| Jan 45 | Disbanded |
Batteries
| Nov 39 | 48, 145, 150 |
| Feb 41 | 48, 145, 150, 231 |
| Sep 41 | 145, 150, 231 |