By the Blitz of late 1940, 50 Searchlight Rgt had been transferred within 2 AA Division to 50th Light AA Bde, responsible for the air defence of Derby and Nottingham. The regiment supplied a cadre of experienced officers and men to 233rd S/L Training Rgt at Saighton Camp where it provided the basis for a new 556 S/L Bty formed on 13 February 1941. This battery later joined a newly-forming 92nd S/L Rgt. In 1941 the searchlight layout over the Midlands was reorganised, so that any hostile raid approaching the Gun Defended Areas (GDA) around the towns must cross more than one searchlight belt, and then within the GDAs the concentration of lights was increased. By the end of the Blitz in May 1941, 50th S/L Rgt was in 50th Light AA Bde in 2nd AA Division, and remained with it until June 1942 when it joined a newly-formed 72nd AA Bde in 2nd AA Division, though 402 and 403 Btys remained attached to 50th AA Bde. On 10 September 1942, 400 (Northampton) Battery was transferred to 30th (Surrey) Searchlight Regiment, Royal Artillery, which was preparing for service overseas. The regiment landed at Algiers in January 1943 and was the only British searchlight unit serving with Allied Force Headquarters (AFHQ) in North Africa. 400 Battery later moved into Tunisia as part of '30/62 S/L Regiment'. During the Italian Campaign, 30 S/L Regiment was once again the only British searchlight unit operating under AFHQ, but late in 1943 it was placed in suspended animation and its personnel dispersed to other units.  50th (Northampton) S/L Rgt remained with 72nd AA Bde until December 1942, when it left to join 47th AA Bde in 2 AA Group (which had replaced 2nd AA Division). It remained with this brigade throughout 1943.  2 AA Group was responsible for defending the assembly camps, depots and embarkation ports for Operation Overlord (the Allied invasion of Normandy) and was planning for the expected onslaught of V-1 flying bombs (codenamed 'Divers') against London. Meanwhile, the group had to deal with a sharp increase in "Luftwaffe" air raids trying to reach London (the so-called 'Baby Blitz'), which continued until May. In June 1944 47 AA Bde was disbanded but 50th S/L Rgt simply transferred within 2 AA Gp to the command of 38th Light AA Bde.