51 (Lowland) Heavy Regiment RA (TA) was converted from 57 Medium Regiment RA (TA) as 2 Heavy Regiment RA (TA) in September 1939. It was re-designated as 51 (Lowland) Heavy Regiment RA (TA) three days later. The unit went to France with the BEF in November 1939. Returning from Dunkirk, the Regiment spent the next four years re-equipping and training. They landed in France in June 1944 shortly after D-Day. They fought through France, Belgium Holland and into Germany. They were involved in many actions including clearing the Reichswald and the Rhine crossing. The Regiment was placed in suspended animation in April 1946 and reconstituted as 357 (Lothians) Medium 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 | Formed from 57 Medium Regiment | UK | |
| Nov 39 | British Expeditionary Force | France | |
| Jun 40 | Home Forces | UK | |
| Apr 44 |  |
2 Army | UK |
| Jun 44 | 4 Army Group RA | Normandy, France | |
| Dec 44 |  |
30 Corps | Belgium |
| Jan 45 |  |
9 Army Group RA, 12 Corps | Holland |
| Feb 45 | 4 Army Group RA | Holland |
Batteries
| Sep 39 | A, B, C, D |
| Mar 42 | P, Q, R, S |
| Jan 43 | 1, 2, 4, 6 |
Equipment
| Sep 39 | 9.2 inch Howitzers (3 batteries), 6 inch Guns (rubber tyre wheels – 1 battery) |
| Jun 44 | 7.2 inch Howitzers, 155 mm Guns (Long Tom) |