17 Light Anti-Aircraft Regiment RA (TA) was formed with two batteries at Chelsea, in December 1938. It moved to Scotland in 1941 before going to North Africa in November 1942 and then to Italy in September 1943. The Regiment was placed in suspended animation in March 1946. 17 Light Anti-Aircraft Regiment RA (TA) was re-constituted as 517 (Essex) Light Anti-Aircraft 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.
| Sep 39 |  |
London District | Chelsea, London, UK |
| Oct 39 |  |
6 Anti-Aircraft Division, 37 Anti-Aircraft Brigade | London, UK |
| Dec 41 |  |
12 Anti-Aircraft Division, 63 Anti-Aircraft Brigade | Western Scotland |
| Nov 42 |  |
1 Army | N Africa |
| Jul 43 |  |
Allied Forces HQ | N Africa |
| Sep 43 |  |
8 Army | Italy |
Batteries
| Sep 39 | 48, 49, 50 |
| Nov 49 | 49, 50, 96, 146 |
| Oct 40 | 50, 96, 146 |
| Sep 41 | 50, 96, 146 , 283 |
| Jul 42 | 50, 96, 146 |