Initially, it formed part of 3rd AA Division, which had responsibility for defending Scotland, Northern Ireland and North East England.

[1][2][3] At the time the brigade was formed, the TA's AA units were in a state of mobilisation because of the Munich crisis, although they were soon stood down.

[17] Luckily, the months of the Phoney War that followed mobilisation allowed AA Command to address its equipment shortages and a Gun Defence Area (GDA) was established around Teesside including Middlesbrough and Billingham.

Vital Points (VPs) such as RAF Fighter Command airfields and factories began to receive a few Bofors LAA guns.

[18] 85th AA Regiment left the brigade in November 1939 to mobilise for overseas service; in April 1940 it joined the British Expeditionary Force in France.

During the early part of the Battle of Britain, German day and night air raids and mine laying began along the East Coast of England, intensifying through June 1940.

Thereafter the Luftwaffe concentrated on Royal Air Force sites in the South of England, with occasional raids on the North East, such as the period 12–15 August.

The cluster system was an attempt to improve the chances of picking up enemy bombers and keeping them illuminated for engagement by AA guns or RAF Night fighters.

The order of battle of 43 AA Bde was now as follows (temporary attachments omitted):[22][23][35][36][37] During 1942 the Luftwaffe switched to 'hit and run' attacks against coastal targets.

[55][56] By late 1943 AA Command was being forced to make manpower cuts, releasing men to 21st Army Group for Operation Overlord, the planned Allied invasion of Normandy, and a number of batteries were disbanded.

Firstly, mobile HAA guns were replaced with static installations that could traverse more quickly to track the fast-moving targets.

The whole process involved the movement of hundreds of guns and vehicles and thousands of servicemen and women, but a new 8-gun site could be established in 48 hours.

The guns were constantly in action, but success rate against the 'Divers' steadily improved, until over 50 per cent of incoming missiles were destroyed by gunfire or fighter aircraft.

This phase of Operation Diver ended in September after the V-1 launch sites in Northern France had been overrun by 21st Army Group.

[67] In October 1944, AA Command began planning to counter the expected attacks by air-launched V-1s coming in across the North Sea against targets on the East Coast and the Midlands.