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 in July 1939 and in June 1940 it became 84 (Middlesex, London Transport) Heavy Anti-Aircraft Regiment RA (TA). The Regiment was placed in suspended animation in November 1944. 84 (Middlesex, London Transport) Heavy Anti-Aircraft Regiment RA (TA) was reconstituted as 484 (Middlesex) (M) Heavy Anti-Aircraft 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.
| Jan 39 |  |
1 Anti-Aircraft Division, 49 Anti-Aircraft Brigade | London, UK |
| Aug 41 | |
1 Anti-Aircraft Division, 26 Anti-Aircraft Brigade | London, UK |
| Oct 41 |  |
War Office Reserve | London, UK |
| Jan 42 |  |
6 Anti-Aircraft Division, 37 Anti-Aircraft Brigade | London, UK |
| Aug 42 | |
6 Anti-Aircraft Division, 56 Anti-Aircraft Brigade | Kent, UK |
| Mar 43 |  |
1 Army, 66 Anti-Aircraft Brigade | Bone, Algeria |
| May 43 | |
1 Army, 52 Anti-Aircraft Brigade | Bizerta, Tunisia |
| Jul 43 |  |
8 Army | Italy |
| Dec 43 | |
8 Army, 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 |