138 (City of London) Field Regiment RA (TA) was formed as a duplicate of 90 (City of London) Field Regiment in April 1939 at Bloomsbury with two batteries . In December 1940 a third battery was formed at Newport, Wales. The Regiment took part in Operations Torch and Husky (N Africa & Sicily). 138 (City of London) Field Regiment RA (TA) went into suspended animation in November 1945 and was disbanded 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.
(Title authorised February 1942)
| Apr 39 |  |
2 (London) Infantry Division | Bloomsbury, London, UK |
| Nov 40 | |
47 Infantry Division | UK |
| Jul 42 |  |
78 Infantry Division | UK |
| Nov 42 | |
78 Infantry Division | N Africa |
| May 43 | |
78 Infantry Division | Tunisia |
| Dec 42 | |
78 Infantry Division | Tebourba Gap, Tunisia |
| May 43 | |
78 Infantry Division | Tunis, Tunisia |
| Jul 43 | |
78 Infantry Division | Sicily |
| Sep 43 | |
78 Infantry Division | Italy |
| May 44 | |
78 Infantry Division | Cassino, Italy |
| Jul 44 | |
78 Infantry Division | Florence, Italy |
| Apr 45 | |
78 Infantry Division | Argenta Gap, Italy |
| May 45 | |
78 Infantry Division | Austria |
Batteries
| Apr 39 | 359 (3rd City of London), 360 (4th City of London) |
| Dec 40 | 359, 360, 502 |
Equipment
| Apr 39 | 18 pdr Guns, 4.5 inch Howitzers |