123 (City of London Rifles) Light Anti-Aircraft Regiment RA (TA) was converted in February 1942 from 31 Searchlight Regiment. The Regiment served mostly with 21 Army Group preparing for D Day. When not training it was loaned to Anti-Aircraft Command. It moved to Normandy in June 1944 and fought with 2 Army through France, Belgium, Holland and Germany. 123 (City of London Rifles) Light Anti- Aircraft Regiment RA (TA) was placed in suspended animation in February 1946 and re-constituted as 566 (City of London Rifles) 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.
| Feb 42 | Formed from 31 Searchlight Regiment | ||
| Feb 42 | Home Forces | UK | |
| Aug 42 |  |
5 Anti-Aircraft Division, 72 Anti-Aircraft Brigade | UK |
| Feb 43 |  |
5 Anti-Aircraft Group, 65 Anti-Aircraft Brigade | UK |
| May 43 |  |
21 Army Group, 103 Anti-Aircraft Brigade | Great Yarmouth, Norfolk, UK |
| Jun 43 | |
21 Army Group, 100 Anti-Aircraft Brigade | Salisbury, Wiltshire, UK |
| Jan 44 | |
21 Army Group, 103 Anti-Aircraft Brigade | Bournemouth, Dorset, UK |
| Mar 44 |  |
2 Army | UK |
| Jun 44 | |
2 Army, 80 Anti-Aircraft Brigade – 405, 409 Batteries only | Normandy, France |
| Aug 44 | |
2 Army, 100 Anti-Aircraft Brigade | River Seine, France |
| Sep 44 | |
2 Army, 100 Anti-Aircraft Brigade | Nijmegen, Holland |
| Mar 45 | |
2 Army, 100 Anti-Aircraft Brigade | Venlo, Holland |
| Mar 45 | |
2 Army, 100 Anti-Aircraft Brigade | Rhine crossing, Holland |
| Apr 45 | |
2 Army, 100 Anti-Aircraft Brigade | River Weser, Germany |
Batteries
| Feb 42 | 405, 408, 409, 410 |
| Oct 42 | 405, 408, 409 |