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

[10][11][12][13][14] The regiment supplied a cadre of experienced officers and men to 234th S/L Training Rgt at Carlisle where it provided the basis for a new 529 S/L Bty formed on 14 November 1940.

[2] The industrial cities of the North Midlands were targets for night bombing by the German Luftwaffe during the winter of 1940–41, the Nottingham Blitz on 8/9 May 1941 being a notable example.

[2][3][17][19] In April 1943 it was redeployed to the command of 5 AA Bde on the South Coast of England at short notice to combat the campaign of 'hit and run' attacks on coastal towns begun by the Luftwaffe in March.

[2][3][5][6][10][24] When the TA was reconstituted on 1 January 1947, 71st S/L Rgt was reformed at Rusholme, Manchester, as 606th (Mixed) Heavy Anti-Aircraft Regiment, RA (East Lancashire), ('Mixed' denoting that members of the Women's Royal Army Corps were integrated into the unit).

A 3.7-inch HAA gun was installed in the drill hall for instructional purposes, and the regiment also had a cadet detachment at Norman Road.

[3][5][25][28] On 1 January 1949, an oak clergy desk was unveiled in St John's Church, Failsworth, bearing the inscription: 'PRESENTED BY THE OFFICERS AND OTHER RANKS OF 71ST (E.L.) SEARCHLIGHT REGIMENT, ROYAL ARTILLERY T.A.