50 (The Northamptonshire Regiment) Searchlight Regiment RA (TA) formed in August 1940 by the transfer of 50 (The Northamptonshire Regiment) Anti-Aircraft Battalion Royal Engineers (TA) to the RA. The Regiment Served in Anti-Aircraft Command until its conversion to an infantry regiment in early 1945. 50 (The Northamptonshire Regiment) Searchlight Regiment RA (TA) was converted to 637 Infantry Regiment RA in January 1945. It went into suspended animation in Feb ruary 1946 and was re-constituted as 585 (The Northamptonshire Regiment) (Mixed) Light Anti-Aircraft/Searchlight 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.
| Aug 40 | Formed from 50 Anti-Aircraft Battalion Royal Engineers | ||
| Aug 40 |  |
2 Anti-Aircraft Division, 32 Anti-Aircraft Brigade | UK |
| Oct 40 | |
2 Anti-Aircraft Division, 50 Light Anti-Aircraft Brigade | Derby, Derbyshire, UK |
| Jun 42 |  |
5 Anti-Aircraft Division, 72 Anti-Aircraft Brigade | Berkshire, UK |
| Dec 42 |  |
2 Anti-Aircraft Group, 47 Anti-Aircraft Brigade | Southern England |
| Jun 44 | |
2 Anti-Aircraft Group, 38 Anti-Aircraft Brigade | Southern England |
| Jan 45 | Became 637 Infantry Regiment RA |
Batteries
| Aug 40 | 400, 401, 402, 403 |
| Sep 42 | 401, 402, 403 |