The Central Government War Headquarters (CGWHQ) is a complex built underground as the United Kingdom's emergency government war headquarters – the hub of the country's alternative seat of power outside London during a nuclear war or conflict with the Soviet Union. It is located in Corsham, Wiltshire, in a former Bath stone quarry known as Spring Quarry, under the present-day MoD Corsham. In 1940, during the Second World War, the site was acquired by the Minister of Aircraft Production and used as an underground engine factory. The complex was known variously as "Stockwell", "Subterfuge", "Burlington", "Turnstile", "Chanticleer", "Peripheral", and "Site 3". It was also nicknamed "Hawthorn" by journalist Duncan Campbell, who first revealed its existence in his 1982 book War Plan UK. It was also mentioned by Peter Laurie in his 1979 revised edition of Beneath the City Streets. It was commissioned in 1955, after approval by Prime Minister Anthony Eden. However it became outdated shortly after it was built, due to intercontinental ballistic missiles being able to target it, and the formulation of other plans (such as PYTHON). Nevertheless the complex continued to have a role in war plans and remained in operation for thirty years. Features Over in length, and with over of roads, the site was designed to accommodate not only the Prime Minister, but also the entire Cabinet Office, civil servants, and an army of domestic support staff. Blast-proof and self-sufficient, the complex could accommodate up to 4,000 people in complete isolation from the outside world for up to three months. The underground city was equipped with all the facilities needed to survive: from hospitals, canteens, kitchens and laundries to storerooms for supplies, accommodation areas and offices. An underground lake and treatment plant could provide drinking water, and twelve tanks could store the fuel required to keep the four generators in the underground power station running for up to three months. The air within the complex could be kept at a constant humidity and heated to around . It was also equipped with the second-largest telephone exchange in Britain, a BBC studio from which the PM could address the nation, and an internal Lamson Tube system that could relay messages throughout the complex, using compressed air. To maintain the secrecy of the site, even during a countdown to war, it was envisaged that 4,000 essential workers would assemble at an outlying destination known as Check Point.