men were invited to volunteer for parachute service, or assigned to a new unit. The new battalions were then brought up to strength from volunteers from other units. The airlanding battalions came from existing infantry units that were converted to glider infantry, and the soldiers did not have the ability to opt-out. The war establishment, the on-paper strength, was set at 12,148 men, with a large number of automatic weapons assigned to the division. The establishment called for 7,171 bolt-action Lee Enfield rifles, 6,504 Sten submachine guns, 966 Bren light machine guns, and 46 Vickers medium machine guns. Each division was also expected to have 392 PIAT anti-tank weapons, 525 mortars, 100 anti-tank guns, and twenty-seven M116 pack howitzers. Just over 6,000 vehicles—primarily jeeps, motorcycles, and bicycles, but also including 22 Tetrarch light tanks—were authorised for each division. Gliders delivered the heavier equipment. Anti-aircraft Between 1935 and the start of the war, the British Army formed anti-aircraft divisions. These formations were part of the Territorial Army, and were not intended to be comparable to other formations such as infantry divisions. The anti-aircraft divisions were assigned to a particular area, which could cover hundreds or thousands of square miles. They varied dramatically in manpower, the number of brigades controlled, and the number of weapons assigned. For example, the 1st Anti-Aircraft Division was assigned to defend London, while the 3rd Anti-Aircraft Division was assigned to defend both Scotland and Northern Ireland. In September 1939, Anti-Aircraft Command's seven divisions had a combined total of 695 heavy anti-aircraft guns compared to an intended 2,232, and 253 light anti-aircraft guns out of an establishment of 1,200. The divisions also had access to 2,700 searchlights, out of a recommended total of 4,700. By 1941, the divisions had 1,691 heavy guns, 940 light guns, and 4,532 searchlights. At the start of the war, the divisions and their command structure had a total of 106,690 men; manpower increased to 157,319 by July 1940, and was over 300,000 by mid-1941. All of the divisions were disbanded in October 1942 as part of a reorganisation of the anti-aircraft command structure. The divisions were replaced by seven groups, which were intended to reduce the overall number of formations, save manpower, and be more flexible. Armoured Between May 1939 and the end of the Second World War, the armoured division went through nine organisational changes. In 1939, it was intended that an