It saw action during the campaign in North West Europe, defending the vital port of Antwerp against V-1 flying bombs and supporting the advance into Germany.

[5] Anti-Aircraft Command's searchlights had been deployed in clusters, but in September 1941 this arrangement was changed and 89th S/L Rgt's lights were redeployed singly to form a 'killer belt' to assist Royal Air Force night-fighters.

[5][6][7] However, in October 1941, 89th S/L Rgt was ordered to redeploy again to provide closely spaced S/L cover within the Plymouth Gun Defence Area (GDA), with RHQ moving to Buckland Filleigh.

The regiment was relieved by 74th (Essex Fortress) S/L Rgt and moved into camp at St Audries, close to the School of AA Instruction at Watchet.

74th AA Brigade was one of the mobile formations created to support 21st Army Group in the Operation Overlord planned invasion of Normandy.

LAA regiments at this time comprised three batteries of three troops, each equipped with six towed Bofors 40 mm guns using Stiffkey Stick sights.

[18] At the end of the month, 21st Army Group broke out from the Normandy beachhead and began to pursue the defeated German troops across Northern France.

[22] By February 1945, 133rd LAA Rgt had rejoined 74th AA Bde with II Canadian Corps for Operation Veritable to clear the Reichswald and break the Siegfried Line.