Admiralty Citadel

A number of military citadels are known to have been constructed underground in central London, dating mostly from the Second World War and the Cold War. Unlike traditional above-ground citadels, these sites are primarily secure centres for defence co-ordination.

A large network of tunnels exists below London for a variety of communications, civil defence and military purposes, however it is unclear how these tunnels, and the various facilities linked to them, fit together, if at all. Even the number and nature of these facilities is unclear; only a few have been officially admitted to.

The most important military citadel in central London is Pindar, or the Defence Crisis Management Centre. The bunker is deep beneath the Ministry of Defence on Whitehall. Construction took ten years and cost £126.3 million. Pindar became operational in 1992, two years before construction was complete. The high cost was controversial. Computer equipment was much more expensive to install than originally estimated as there was very little physical access to the site.

Pindar's main function is to be a crisis management and communications centre, principally between the MOD headquarters and the actual centre of military operations, the Permanent Joint Headquarters in Northwood. It is reported to be connected to Downing Street and the Cabinet Office by a tunnel under Whitehall. Despite rumours, armed Forces Minister Jeremy Hanley told the House of Commons on 29 April 1994 that "the facility is not connected to any transport system."

Although the facility is not open to the public, it has had some public exposure. In the 2003 BBC documentary on the Iraq conflict, Fighting the War, BBC cameras were allowed into the facility to film a small part of a teleconference between ministers and military commanders. Also, in 2008 the British photographer David Moore published his series of photographs, The Last Things, widely believed to be an extensive photographic survey of Pindar. Photographs taken of the facility in 2008 show that it has stores including toothpaste, toothbrushes, and mouthwashes. It has bunks for up to 100 military officers, politicians and civilians as well as communication facilities, a medical centre and maps.

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