RAF munitions storage during World War II

The logistics organizations of the Royal Air Force in World War II were No. 42 Group RAF and RAF Maintenance Command.

As a result of a serious shortage of funds during the inter-war period and a weakness of policy, the RAF was singularly ill-equipped to deal with the requirements of air warfare for the protected storage of explosives. In 1936 the RAF had only three ammunition dumps: at Sinderland, Cheshire; Chilmark, Wiltshire; and Pulham St Mary, Norfolk. The latter and former sites' storage consisted of metal sheds connected by standard gauge rail tracks. In 1935 the standard bomb of the RAF was a 250 lb (110 kg) device containing high explosives, the largest bomb being 500 lb (230 kg).

There had been some small-scale use of underground munitions stores in Britain during the First World War, although these were more general purpose than specifically for the RAF. Chislehurst Caves were bought in October 1914 and a small portion of the twenty miles (32 km) of tunnels was prepared for storing up to 1,000 tons of explosives and raw materials for the Royal Arsenal, Woolwich, nine miles (14 km) away. Similarly, at the Chilwell Ordnance Factory a nearby hillside was bored out with a T-shaped storage area in 1915 as part of a total £2.5 million spent on the site, but this could hold barely 300 tons of matériel. Other sites were also acquired but with the end of the conflict all fell into disuse.

The Air Ministry estimated in 1936 that a war reserve would contain 98,000 tons of bombs, 82,000 as 250 lb (110 kg) and 500 lb (230 kg) bombs and the balance as incendiaries; to save money only 48,000 tons was purchased. The RAF decided to store these weapons in a number of underground depots, each holding 10-30,000 tons. The decision to expend the extra money to store the matérial underground was taken because the thin-walled bombs and inflammable incendiaries were extremely vulnerable to blast, much more so than artillery shells.

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