By the end of 1944, 21st Army Group fighting in North West Europe was suffering a severe manpower shortage, particularly among the infantry. At the same time, the German "Luftwaffe" was suffering from such shortages of pilots, aircraft and fuel that serious aerial attacks on the United Kingdom could be discounted. The War Office began to reorganise surplus AA regiments in the UK into infantry battalions, primarily for line of communication and occupation duties, thereby releasing trained infantry for front-line service.