Prior to World War II, in May 1924, an Air Raid Precautions Committee was set up in the United Kingdom. For years, little progress was made with shelters because of the apparently irreconcilable conflict between the need to send the public underground for shelter and the need to keep them above ground for protection against gas attacks. In February 1936 the Home Secretary appointed a technical Committee on Structural Precautions against Air Attack.
By November 1937, there had only been slow progress, because of a serious lack of data on which to base any design recommendations, and the Committee proposed that the Home Office should have its own department for research into structural precautions, rather than relying on research work done by the Bombing Test Committee to support the development of bomb design and strategy. This proposal was eventually implemented in January 1939.
During the Munich crisis, local authorities dug trenches to provide shelter. After the crisis, the British Government decided to make these a permanent feature, with a standard design of precast concrete trench lining. Unfortunately these turned out to perform very poorly. They also decided to issue free to poorer households the Anderson shelter, and to provide steel props to create shelters in suitable basements.
Air raid shelters were built specifically to serve as protection against enemy air raids. However, pre-existing edifices designed for other functions, such as underground stations (tube or subway stations), tunnels, cellars in houses or basements in larger establishments, and railway arches, above ground, were suitable for safeguarding people during air raids. A commonly used home shelter known as the Anderson shelter would be built in a garden and equipped with beds as a refuge from air raids.
Cellars have always been much more important in Continental Europe than in the United Kingdom, and especially in Germany almost all houses and apartment blocks have been and still are built with cellars. For this reason, air-raid precautions during World War II in Germany could be much more readily implemented by the authorities than was possible in the UK. All that was necessary was to ascertain that cellars were being prepared to accommodate all the residents of a building; that all the cellar hatch and window protections were in place; that access to the cellars was safe in the event of an air raid; that once inside, the occupants were secure for any incidents other than direct hits during the air raid; and that means of escape in case of a real emergency were easily available.