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The Battle of Britain Bunker is an underground operations room at the site of the former RAF Uxbridge. Following excavations in 1938, the Bunker was constructed in top-secrecy between February and August 1939 by Sir Robert McAlpine. The floor of the Bunker is 60 ft underground and is accessed by a staircase of 76 steps. The walls, floor and ceiling are approximately 1 metre thick and are made of concrete with waterproof lining. The solid concrete walls and the approximately 30 ft of earth above the Bunker's ceiling meant that no bomb of the period could penetrate it. A ventilation and air filtration system, which still functions well, was installed to provide an air supply to the Operations Room staff.

The bunker was used by No. 11 Group Fighter Command during the Second World War. Fighter aircraft operations were controlled from there throughout the War but most notably during the Battle of Britain and on D-Day. Today it is run by Hillingdon Council as a heritage attraction with attached museum. A new visitor centre above ground opened in March 2018.

The Group Operations Room is a Grade I Listed Building (List Entry Number: 1392556) Link
Wikipedia: Link
Visitor site: Link