84 Anti-Aircraft Brigade RA(TA) was raised in October 1938 at Tottenham, London. It was re-designated as 84 Anti-Aircraft Regiment RA(TA) in January 1939. It was re-titled 84 Middlesex (London Transport) Anti-Aircraft Regiment RA(TA) in July 1939 and in June 1940 it was re-designated as 84 (Middlesex, London Transport) Heavy Anti-Aircraft Regiment RA(TA). The Regiment was placed in suspended animation in November 1944 and reconstituted as 484 (Middlesex) (M) Heavy Anti-Aircraft Regiment RA(TA) in January 1947.
| Jan 39 | 49 Anti-Aircraft Brigade, 1 Anti-Aircraft Division | London, UK |
| Aug 41 | 26 Anti-Aircraft Brigade, 1 Anti-Aircraft Division | London, UK |
| Oct 41 | War Office Reserve | London, UK |
| Jan 42 | 37 Anti-Aircraft Brigade, 6 Anti-Aircraft Division | London, UK |
| Aug 42 | 56 Anti-Aircraft Brigade | Kent, UK |
| Mar 43 | 66 Anti-Aircraft Brigade | Bone, Algeria |
| May 43 | 52 Anti-Aircraft Brigade | Bizerta, Tunisia |
| Jul 43 | 8 Army | Italy |
| Dec 43 | 2 Anti-Aircraft Brigade | River Sangro, Italy |
| Nov 44 | Suspended animation |
Batteries
| Jan 39 | 260 (London Transport), 261 (London Transport), 262, 263 |
| Apr 40 | 260 Battery detached for Norway campaign |
| Feb 43 | 260, 262, 263 |
