Secret wartime targeting bunker opens to visitors beneath Dover’s white cliffs

A command bunker buried four metres inside Dover’s white cliffs opens to the public on Friday, November 13, offering access to a wartime facility built on Winston Churchill’s orders. The concrete plotting room at Fan Bay helped direct a gun battery that defended Dover and attacked German shipping in the Channel.

According to Jon Stewart, who led the National Trust’s excavation project, the bunker contained the first land-based computer-aided targeting system. Its central equipment was a 1.8-metre-long electromechanical computer called a fire direction table. It calculated where moving ships would be when shells reached them and relayed firing instructions to the gun crews.

The battery’s origins lie in Churchill’s visit to the Kent coast shortly after his “fight them on the beaches” speech. He was alarmed to see enemy vessels moving through the strait of Dover without challenge, while Dover itself faced repeated bombardment from German guns in occupied France. In July 1940, he called for artillery to secure control of the straits, demanding advanced technology and weekly progress reports. The guns were ready within 100 days, with the plotting bunker finished another 64 days later.

Evidence of the rushed construction survives in rough openings made for cables through the bunker’s walls and floors. Accounts from the period describe equipment being installed before drawings setting out its layout were available. Stewart said the guns became known locally as “Churchill’s pets”. The computer was deliberately destroyed in 1957 to prevent it reaching enemy hands, and the bunker was secretly mothballed that year. Its military significance kept it classified until 1981.

Stewart became the first person to enter the rediscovered bunker in 2017. He described the experience as “a Tutankhamun moment for a conflict archaeologist”, after researching people who had served there and then entering their workplace. As many as 10 people worked in the plotting room at once, but only a few operators have been identified. They include actor Wallas Eaton, who later played Senator Ludicrus Sextus alongside Frankie Howerd in Up Pompeii, and lance bombardier WP Bryant, a tailor recorded as a plotter.

With records limited, Stewart hopes relatives of former Fan Bay personnel can help explain how the computer operated. The team’s understanding currently draws on a manual and traces left on the floor. He compared the discovery with the rescue of the Bletchley Park codebreaking site in the 1990s, describing the plotting room as another hidden history.

Visitors will enter through a hatch in a field on National Trust guided tours. The room has been conserved much as the excavation team found it, retaining newspapers, shoes and official notices. Chalk graffiti in a service tunnel names Dodds and Petitt, whom Stewart suggested may have helped install cables. The approach preserves the surviving evidence of the people who built and worked in the bunker.