18 Light Anti-Aircraft Regiment RA (TA) was formed with two batteries at Glasgow, in December 1938. It moved to Iraq in June 1942 serving in the Middle East, Sicily and Italy. Most of its service was with 5 Infantry Division and it moved to North West Europe with them in March 1945. The Regiment was placed in suspended animation in November 1946. 18 Light Anti-Aircraft Regiment RA (TA) was re-constituted as 518 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.
| Sep 39 |  |
Scottish Command | Glasgow, UK |
| Nov 40 |  |
12 Anti-Aircraft Division, 42 Anti-Aircraft Brigade | Western Scotland |
| Aug 41 | |
12 Anti-Aircraft Division, 63 Anti-Aircraft Brigade | Western Scotland |
| Jun 42 |  |
10 Army | Iraq |
| Sep 42 | PAI Force | Iraq | |
| Feb 43 |  |
5 Infantry Division | Syria |
| Jun 43 | |
5 Infantry Division | N Africa |
| Jul 43 | |
5 Infantry Division | Sicily |
| Sep 43 | |
5 Infantry Division | Italy |
| Jul 44 | |
5 Infantry Division | Palestine |
| Feb 45 | |
5 Infantry Division | Italy |
| Mar 45 | |
5 Infantry Division | NW Europe |
Batteries
| Sep 39 | 54, 56, 99, 139 |
| Apr 41 | 54, 56, 99, 139, 252 |
| Aug 41 | 56, 99, 139, 252 |
| Dec 42 | 99, 139, 252 |