171 (Mixed) Heavy Anti-Aircraft Regiment RA (TA) was formed at Cardiff in August 1942. It became a non-mixed unit in August 1945. The Regiment served with Anti-Aircraft Command for its entire war. 171 (Mixed) Heavy Anti-Aircraft Regiment RA (TA) was considered a new War Formed Regiment in January 1947 and in the April was re-designated 102 Heavy Anti-Aircraft Regiment RA.
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 42 | Formed | Cardiff, UK | |
| Aug 42 |  |
3 Anti-Aircraft Group, 45 Anti-Aircraft Brigade | South Wales, UK |
| Nov 44 | |
1 Anti-Aircraft Group, 26 Anti-Aircraft Brigade | South East England |
| Dec 44 | |
1 Anti-Aircraft Group, 48 Anti-Aircraft Brigade | South East England |
| Aug 45 | Became 171 Heavy Anti-Aircraft Regiment (No longer mixed) |
Batteries
| Aug 42 | 474 (Mixed), 496 (Mixed) |
| Oct 42 | 474 (M), 496 (M), 569 (M), 580 (M) |
| May 43 | 474 (M), 496 (M), 569 (M) |
| Dec 44 | 474 (M), 496 (M) |
| Jan 45 | 474 (M), 496 (M), 500 (M) |