“All the world that is still free marvels at the composure and fortitude with which the citizens of London are facing and surmounting the great ordeal to which they are subjected, the end of which or the severity of which cannot yet be foreseen.”

Winston Churchill broadcast these words from a secret underground command center in central London on September 11, 1940, just after Germany began bombing the city. Now known as Churchill’s War Rooms, the complex was situated beneath Whitehall and, for the next five years, would serve as the center of wartime operations.

The site contained numerous important functions including the Map Room, for charting the course of the war, a broadcasting room and, most crucially, the Cabinet Room. With tables laid out in a horseshoe configuration, this is where the heads of Army, Navy and Air Force would meet with Churchill. It was, in Churchill’s words, “the room from which I’ll direct the war.”

Churchill’s desk in his underground bedroom, where he made four of his wartime speeches. © IWM SITE CWR 632

These inner workings are the subject of a new book by Jonathan Asbury, Secrets of Churchill’s War Rooms. The book provides fascinating details of life in this top-secret, subterranean space, such as the portable sun lamp used by staff who spent long hours underground; the specially designed gas masks that would allow switchboard operators to continue working even in the event of an attack; and the top-secret Transatlantic Telephone Room, which was given a toilet-stall style lock so staff presumed it was just Churchill’s own private lavatory.

After the war, the Churchill War Rooms were left abandoned until 1984, when they were re-opened to the public by the Imperial War Museum. Secrets of Churchill’s War Rooms draws from personal accounts of staff, archival photographs and images of the restored rooms to provide a behind the scenes look at this once-secret space. AO has a selection of images.

The switchboard operators and typists “were all civilian women. During the Blitz, many of them remained underground day and night, working here and sleeping between shifts in the sub-basement.” © IWM MH 531

The telephone from General Ismay’s room. “The stark cautionary message on this telephone reveals the importance of secrecy above all else.” © IWM SITE CWR 617

On the left is the internal door that led down into the War Rooms. The double doors at center led to the annex of 10 Downing Street, where Churchill and family lived from December 1940. © IWM MH 000520

Churchill’s War Rooms bedroom. © IWM

The map room, 1945. © IWM MH 27688

Entrance pass belonging to Wing Commander J S Heagerty. “Gaining access to the War Rooms meant running past a strict set of security checks. Staff were issued with passes like this one, which they were expected to show without fail to the guards as they passed.” © IWM Documents.2995

Large map from the Map Room Annexe. “It charts in great detail the devastating advance of the German forces in Russia in 1941 – 1942 and their gradual retreat in the years that followed.” © IWM SITE CWR 654

Churchill’s cigar. © IWM

Portable sun lamp. “To alleviate the health problems associated with working underground for prolonged periods of time, staff were made to strip to their underwear, put on a pair of protective goggles and stand in front of portable sun lamps like this one.” © IWM SITE CWR 106