Its initial order of battle was as follows:[1][2] Brigadier Frederick Hyland, MC, was appointed to command 31 AA Brigade at the time of its creation on 1 November 1936.

31 AA Bde reported that out of 1000 recruits sent for duty, '50 had to be discharged immediately because of serious medical defects, another 20 were judged to be mentally deficient and a further 18 were unfit to do any manual labour such as lifting ammunition'.

During this period the brigade was composed as follows (temporary attachments omitted):[22][39][40][41][42] By August 1943, 31 AA Bde was a purely searchlight formation, with the following order of battle:[50] Early in 1944, 31 AA Bde under the command of Brigadier E. Coley was earmarked for overseas service with 21st Army Group in Operation Overlord.

At the time the brigade was headquartered at Tadcaster, later at nearby Newton Kyme, in North Yorkshire as part of 5 AA Group with the following searchlight units under command:[51][52] The regiments re-equipped their AA LMG sections with twin Browning machine guns and carried out 'Bullseye' exercises over North East England with the Night fighters of No.

85 Group RAF was responsible for night-fighter cover of the beachhead and bases in Normandy, and was keen to have searchlight assistance in the same way as Fighter Command had in the UK.

These would be allocated by fighter controllers, and the S/Ls would assist by illuminating targets and indicating raid approaches, while area boundaries would be marked by vertical S/Ls.

In the end, only 41 S/L Regt and the Royal Corps of Signals section of 42 S/L Rgt deployed along the western part of the layout planned by 85 Group, and came under US command.

[59][60] The brigade proceeded to Brussels, where it was given the task of setting up a practice camp for training operators on the new Mk VIII centimetric Searchlight Control (SLC or 'Elsie') radar.

This meant that apart from its Signals and Royal Electrical and Mechanical Engineers sections, the only troops under the brigade's command were a detachment of 41 S/L Rgt personnel attached for the counter-mortar trials.

[59][63] Early in 1945, in preparation for the forthcoming offensive in the Klever Reichswald (Operation Veritable), 31 AA Bde carried out experiments in Belgium to optimise 'artificial moonlight' techniques whereby S/L units provided lighting for night movement of ground troops, for floodlighting their objectives and for dazzling the defenders.