143rd Heavy Anti-Aircraft Regiment was an air defence unit of Britain's Royal Artillery formed during World War II.

By 1941, after two years of war Anti-Aircraft Command, tasked with defending the UK against air attack, was suffering a manpower shortage.

In April its commander-in-chief, Lieutenant-General Sir Frederick 'Tim' Pile, proposed to overcome this by utilising the women of the Auxiliary Territorial Service (ATS).

The ATS was by law a non-combatant service, but it was decided that Defence Regulations permitted the employment of women in anti-aircraft (AA) roles other than actually firing the guns.

The male soldier intake of these batteries were men transferred from recently formed Light AA (LAA) units, the majority of the personnel were women from the ATS.

[5][9][10][11] Although there were a number of Luftwaffe air raids on cities in the West of England during the so-called Baedeker Blitz of 1942, none directly affected the Gloucester area.

The South Coast was under attack from 'hit-and-run' raids by fighter-bombers and brigade HQ was transferred on 8 November command LAA reinforcements being sent to the area.

[1][17] In early 1944, however, the Luftwaffe began a new campaign, the so-called 'Baby Blitz', that brought several raids over the West Country from February onwards.

[18][19] In March 1944, 143rd (M) HAA Rgt moved to 55 AA Bde covering the Plymouth–Falmouth area where shipping was being gathered for the Allied invasion of Normandy (Operation Overlord).