The unit was formed as 2 East Anglian Brigade Royal Field Artillery (TF) in February 1920 at Stratford. The Brigade became 85 (East Anglian) Brigade Royal Field Artillery (TA) in 1921. It changed its title again in June 1924 becoming 85 (East Anglian) Field Brigade RA (TA). 85 Field Brigade was re-designated 85 (East Anglian) Field Regiment RA (TA) in November 1938 with two batteries. In November 1940, a third battery was formed at Gosforth Park. Originally formed as R Battery, by January 1941 it had been numbered as 461 Battery. In September 1943 it converted to 85 (East Anglian) Mountain Regiment RA (TA). Post war 85 (East Anglian) Field Regiment RA (TA) went into suspended animation in September 1945 and was re-constituted as 285 (Essex) Airborne Light 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.
| 3 Sep 39 |  |
54 Infantry Division | Stratford, West Midlands, UK |
| Nov 42 |  |
British Troops Egypt | Egypt |
| Jan 43 |  |
5 Indian Division | Iraq |
| Apr 43 |  |
21 Indian Corps | Iraq |
| Sep 43 | Became 85 Mountain Regiment |
Batteries
| 1921 | 337, 338, 339, 340 |
| Oct 32 | 213, 337, 338, 340 |
| Nov 38 | 337 (Essex), 338 (Essex) – 213 & 340 Batteries to 134 Field Regiment |
| Nov 40 | 337, 338, 461 |