The Imperial War Museum is a multi-branch national museum founded in 1917 to record the story of the Great War and the contributions made by the peoples of the Empire to it. The Museum and its governing body, the Board of Trustees, were formally established by Act of Parliament in 1920, when the Museum opened in the Crystal Palace. From 1924 to 1935 the Museum was housed in two small galleries adjoining the Imperial Institute. In 1936 it was reopened in the central portion of the former Bethlem Royal Hospital in Lambeth Road, Southwark where it remains.
In 1939 the Trustees' remit was extended to include the Second World War and in 1953 the terms of reference were further expanded to include all military operations in which British or Commonwealth forces have been involved since August 1914. The Imperial War Museum is thus the national museum of twentieth century conflict. It illustrates and records all aspects of modern war, and of the individual's experience of war, whether allied or enemy, service or civilian, military or political, social or cultural. Its rôle embraces the causes, course and consequences of conflict and it has an essentially educational purpose.
The Trustees seek to collect every type of evidence documenting their very broad terms of reference and thus maintain collections of works of art, which include over 15,000 paintings, drawings and sculptures and 30,000 posters; objects ranging from aircraft, armoured fighting vehicles and naval vessels to uniforms, badges, personal equipment, and medals and decorations; documents, both British and foreign; printed books comprising a national reference library of over 155,000 items; 120 million feet of cine film and over 6,500 hours of video tape; over 6 million photographs and photographic negatives and transparencies, and some 32,000 recorded hours of historical sound recordings.
The Imperial War Museum is therefore in addition to its conventional museum rôle a major national art gallery, a major national archive of written and audio-visual records, and a research centre. Its activities include display, education, publishing, research, trading, conferences, as well as the acquisition, documentation, study and conservation of collections.
In 1966 the first major extension of the Museum's Lambeth Road building was completed. This provided for the storage of art and archive collections, photographic darkrooms, and workshops. But there had been no addition to Lambeth Road's galleries to match its enlarged remit and collections since 1936, and no significant provision for maintaining the old building and for visitor services. In 1986 work began on Stage 1 of comprehensive renovation and development of the Lambeth Road building aimed at increasing the limited display space, providing facilities appropriate to an internationally important museum and restoring the dilapidated buildings to modern standards. Stage 1 cost £16.7 million. The Government required the Trustees to contribute £4.5 million which was raised by public appeal and from self-generated revenue. It was completed in March 1989 and opened by The Queen on 29 June 1989. Construction of Stage 2, the four storey East Infill, providing over 1,500 square metres of new and refurbished galleries, was completed at the end of 1994 at a cost of £2.2 millions, all self-generated. Construction of the third and final stage of 5,300 square metres, comprising a purpose-built education centre, temporary and permanent exhibition galleries and the national Holocaust Exhibition, supported by the Heritage Lottery Fund, began in June 1997.
Three further Imperial War Museum branches were established in the 1970s and 1980s. In 1976 Duxford Airfield in Cambridgeshire was formally acquired both as a store for reserve collections of objects, records and works of art and as a now highly successful public museum operated jointly through the Duxford Executive Panel by the Trustees and Cambridgeshire County Council, which owns the runway. In 1978 HMS Belfast, the 11,500 ton Second World War cruiser, preserved as a museum ship and moored in the Pool of London since 1971 by a private trust, was incorporated into the Museum. Thirdly, in 1984 the Cabinet War Rooms in Whitehall were opened to the public as a museum. On 1 April 1989 the Trustees assumed full responsibility for this site, which they had previously managed for the Secretary of State for the Environment. In addition, the Museum has a purpose-built film store on the Government site at Hayes, Middlesex and, since 1986, an annexe to Lambeth Road housing mainly the audio-visual records departments at the former All Saints Hospital in Austral Street, London SE11. Thus, the Imperial War Museum is now a multi-branch national museum on six sites, four of which are open to the general public, and all of which are integral elements of the Museum. The Trustees' plans for establishing a fifth branch to serve the North of England in partnership with Trafford Metropolitan Borough Council and Peel Holdings plc, which has contributed a site and £10 millions to a funding package amounting to £28.5 million including a European Regional Development Fund grant of £8.1m, were announced in January 1999.