56 (Cornwall) Heavy Anti-Aircraft Regiment RA (TA) was originally raised as a Medium Regiment in 1920, as 51 (Cornwall and Warwickshire) Medium Brigade RA (TA) at St Austell in Cornwall. It converted to Anti-Aircraft in October 1932 as 56 (Cornwall) Anti-Aircraft Brigade RA (TA) at Falmouth in Cornwall. The unit was re-designated as 56 (Cornwall) Anti-Aircraft Regiment RA (TA) in January 1939, becoming 56 (Cornwall) Heavy Anti-Aircraft Regiment RA (TA) in June 1940. It was re-designated as “B” Medium Regiment RA(TA) in June 1940 and re-designated two weeks later as 56 (Cornwall) Medium Regiment RA (TA) . The Regiment was converted to 86 (Cornwall) Medium Regiment RA (TA) in August 1944. It was placed in suspended animation in May 1946 and was reconstituted as 456 (Cornwall) 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.
| Sep 39 |  |
5 Anti-Aircraft Division, 35 Anti-Aircraft Brigade | Plymouth, Devon, UK |
| Sep 40 |  |
8 Anti-Aircraft Division, 55 Anti-Aircraft Brigade | Plymouth, Devon, UK |
| Mar 42 | Madras Area | India | |
| May 42 |  |
North Western Army, 13 Anti-Aircraft Brigade | Bombay/Madras area, India |
| Feb 43 | |
North Western Army, 3 Indian Anti-Aircraft Brigade | Bombay/Madras area, India |
| Feb 44 | |
North Western Army, 9 Anti-Aircraft Brigade | Bombay/Madras area, India |
| Mar 44 |  |
33 Indian Corps | Galunche, India |
| Jul 44 | |
North Western Army, 9 Anti-Aircraft Brigade | Poona, India |
| Jul 44 | Became 86 Medium Regiment |
Batteries
| Sep 39 | 165, 201, 202, 203 |
| Dec 41 | 165, 201, 202 |
| Mar 43 | 154, 165, 201 |
| Jul 44 | 165, 201 |