As the international situation deteriorated in the late 1930s, the threat of air raids on the UK led to a rapid expansion in the numbers of anti-aircraft (AA) units manned by members of the part-time TA.

In daylight, the Royal Observer Corps and searchlight detachments tracked the progress of raids visually; at night, sound location had to be used.

1st AA Division devised a system of 14 fixed base-lines of sound locators to detect night raids approaching the London Inner Artillery Zone.

These were linked by automatic telephone equipment to the operations room, where the angular plots were resolved to indicate grid squares where the Heavy AA guns in range could fire an unseen barrage.

[15] The regiment was then despatched to the Mediterranean to join Eighth Army for the Allied invasion of Sicily (Operation Husky).

The town of Pachino was quickly secured, and 75th LAA's Bofors guns landed shortly afterwards to contribute to the AA defence of its airfield.

[16][17] Eighth Army captured the port of Taranto on the Italian mainland in September 1943 (Operation Baytown), and during October 8th AA Bde was landed there to defend the disembarkation ports and airfields in the 'heel' of Italy (southern Puglia) in a joint air defence organisation with the RAF.