Raised as 40 Brigade in 1900, it was re-designated as 12 Brigade Royal Field Artillery in May 1920. The Brigade changed from Royal Field Artillery to Royal Artillery in June 1924. The Regiment was re-designated as 12 Field Regiment RA from 12 Field Brigade RA in May 1938. In April 1939 it re-organised on a two battery basis. By November 1941 it had become three batteries. It was re-designated as 17 Medium Regiment RA in November 1943.
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 |  |
Scottish Command | Dunbar, East Lothian, UK |
| Nov 40 |  |
HQRA Malta | Malta |
| Mar 42 |  |
Middle East Forces | N Africa |
| Nov 43 | Became 17 Medium Regiment |
Batteries
| May 22 | 6, 23, 49, 91 |
| Apr 39 | 6/23, 49/91 |
| Nov 41 | 6, 23, 49/91 |
Equipment
| Nov 40 | 24 x 18/25 pdr Guns |