90 Anti-Tank Regiment RA was converted from 9th Battalion The King’s Own Royal Regiment in December 1941 with four batteries. 90 Anti-Tank Regiment RA was disbanded in December 1943 at Old Barracks, Downpatrick.
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.
| Dec 41 | Formed from 9th Battalion King’s Own Royal Regiment (Lancaster) | ||
| Dec 41 | Home Forces | UK | |
| Feb 42 |  |
45 Infantry Division | UK |
| Dec 43 | Disbanded | Downpatrick, Co Down, UK |
Batteries
| Dec 41 | P, Q, R, S |
| Mar 42 | Q, R, S, T |
| Jan 43 | 140, 142, 143 – 141 to 94 Anti-Tank Regiment |
| Jun 43 | 140, 142, 143, 343 |