Formed in July 1938 as 11 Royal Horse Artillery (Honourable Artillery Company) (TA) with two batteries, re-organised from 11 (HAC & City of London Yeomanry) Brigade RHA(TA). A third battery was formed in November 1940. 11 Royal Horse Artillery (Honourable Artillery Company) (TA) went in to suspended animation in December 1945 and was reconstituted as 1 Regiment HAC RHA (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.
| 3 Sep 39 |  |
London District | Finsbury, London, UK |
| Sep 39 | |
London District | Elstree, Hertfordshire, UK Guarding vulnerable points in London |
| May 40 | Home Forces | Swanage, Dorset, UK | |
| Jul 40 |  |
1 Support Group | Corfe Castle, Dorset, UK A Battery attached 1 Royal Horse Artillery until Aug 40 |
| Aug 40 | |
1 Support Group | Loxwood, Sussex, UK |
| Oct 40 | |
1 Support Group | Shere, Surrey, UK |
| Jun 41 | |
1 Support Group | Hungerford, Berkshire, UK |
| Dec 41 | |
1 Support Group | Tobruk, Libya |
| Jan 42 | Jock columns | El Agheila area, Libya | |
| Mar 42 | |
2 Armoured Brigade Group | Gazala, Libya |
| Jun 42 | |
2 Armoured Brigade Group | Knightsbridge Box, Libya |
| Jun 42 | |
2 Armoured Brigade Group | Acroma Ridge, Libya |
| Aug 42 |  |
8 Armoured Division | Sollum, Egypt |
| Aug 42 | |
1 Armoured Division | Mersa Matruh, Egypt |
| Oct 42 | |
1 Armoured Division Attached 50 Division – 6 guns only |
Alamein, Egypt |
| Jan 43 |  |
50 Division | Tmimi, Libya |
| Feb 43 | |
2 Armoured Brigade | Tmimi, Libya |
| Mar 43 | |
2 Armoured Brigade | Medenine, Tunisia |
| Mar 43 | |
2 Armoured Brigade | El Hamma, Tunisia |
| Apr 43 | |
2 Armoured Brigade | Oudref, Tunisia |
| Apr 43 | |
2 Armoured Brigade | Mezzouna, Tunisia |
| May 43 | |
2 Armoured Brigade | Medjez El Bab, Tunisia |
| May 43 | |
2 Armoured Brigade | Bou Ficha, Tunisia |
| May 43 |  |
51 (Highland) Division | Djidjelli, Algeria |
| Jun 43 | |
51 (Highland) Division | Sousse, Tunisia |
| Jul 43 |  |
8 Army | Pachino, Sicily |
| Jul 43 | |
8 Army | Vizzini, Siciliy |
| Jul 43 | |
8 Army | Scordia, Sicily |
| Jul 43 | |
8 Army | Gerbini, Sicily |
| Jul 43 | |
8 Army, 5 Army Group RA | Ramacca, Sicily |
| Aug 43 | |
8 Army, 23 Armoured Brigade | Catenanova, Sicily |
| Aug 43 | |
8 Army, 23 Armoured Brigade | Regalbuto, Sicily |
| Aug 43 | |
8 Army, 23 Armoured Brigade | Catania, Sicily |
| Sep 43 | |
8 Army, 4 Armoured Brigade | Catania, Sicily |
| May 44 | |
1 Armoured Division | Italy |
| Sep 44 | |
8 Army | Italy |
Batteries
| 3 Sep 39 | A, B |
| Nov 40 | A, B, E |
Equipment
| Jun 42 | 25 pdr & Quads – Stuart Observation Post Tanks |
| Sep 42 – Nov 44 | M7 105 mm Self Propelled Priest |