Churchill's Secret Targeting Computer Emerges from the White Cliffs After 67 Years Underground

A concrete bunker housing Britain's first land-based computer-aided targeting system opens to the public, preserved almost exactly as its operators left it in 1957.

Four metres into the white cliffs of Dover, behind a hatch in a field, sits a concrete room that ran the mathematics of killing ships. The Fan Bay plotting room — sealed in 1957, classified until 1981, physically rediscovered in 2017 — opens to National Trust guided tours this Friday. It housed a 1.8-metre electromechanical computer called a fire direction table that calculated where moving ships would be when shells arrived, then sent firing solutions to gun crews above. This is not a museum reconstruction. It is the actual room, preserved as found. The bunker traces directly to Churchill's personal anxiety. After his 'fight them on the beaches' speech in 1940, he visited the Kent coast and watched enemy ships pass through the strait of Dover unchallenged. Dover itself was under regular bombardment from German guns in occupied France. His July 1940 memo demanded artillery command of the straits and weekly progress updates. The guns were operational within 100 days; the plotting room bunker followed 64 days later. The speed shows: rough-cut cable openings through walls and floors, equipment installed before layout drawings existed. Jon Stewart, the conflict archaeologist who led the National Trust excavation and was the first person to enter the rediscovered bunker, calls it 'a Tutankhamun moment.' The comparison to Bletchley Park is his, and it's apt in a specific way — both are sites where electromechanical computation did war-critical work that was then hidden from public memory for decades. The plotting room's fire direction table was deliberately destroyed in 1957 to prevent it falling into enemy hands. What remains are ghost markings on the floor, a manual, and very few identified operators. The known operators are wonderfully specific. Wallas Eaton later played Senator Ludicrus Sextus in Up Pompeii alongside Frankie Howerd. A lance bombardier named WP Bryant was a tailor — 'he probably had a head for numbers,' Stewart notes. Chalked graffiti in a service tunnel reads 'heroes fan hole Dodds and Petitt,' likely self-appointed cable-running heroes who marshalled thick wiring through tight tunnels. Stewart is actively seeking descendants of anyone who served there, because the operational records are scant and the machine's exact workings remain partly mysterious. What makes this site distinctive is the decision not to reconstruct. The National Trust preserved it as found: old newspapers on the floor, abandoned shoes, official notices still on walls. Stewart's framing is precise — 'rather than recreate the past, we've carefully conserved the plotting room so visitors can experience it much as we found it.' This is heritage as forensic preservation rather than interpretive theatre, and for a certain kind of visitor it will be far more powerful for it. The wider significance sits at the intersection of computing history and military heritage. The fire direction table was, as Stewart emphasises, not the glamorous map-and-markers plotting of war films but a genuine electromechanical computer solving real-time ballistic calculations. It represents a thread of computational history that runs parallel to Bletchley's codebreaking but has received almost no public attention. Its opening adds a genuinely new site to Britain's WWII heritage landscape. Access is via National Trust guided tours through the field hatch, groups of limited size. The cliffs of Dover are already one of England's most visited landscapes. Whether this bunker achieves anything like Bletchley's public profile depends on whether the story of a destroyed computer and ghost markings on a floor can compete with Enigma's narrative drama. The raw material is there. The storytelling infrastructure is what matters now.