One Hundred and twenty feet under the village of Corsham ,Wiltshire lies a hidden relic of the Cold War, a place that in the event of Nuclear War would have become the beating heart of Central Government a place where decision would be made to protect those left in the nuclear wastelands of Great Britain.
The Central Government War Headquarters (CGWHQ) is just a small part of what is under your feet as you stand on the surface
It is built in a vast Bath stone quarry that was converted Before World War 2 (1937) into a Central Ammunitions Depot with at least 350,000 tons of ammunition stored safely away from German bombers.
The Royal Engineers were tasked with the mammoth task of removing tons of loose stone. They cleared the old wooden roof supports and replaced them with concrete pillars that created more storage areas.
Fighter Command South West was also housed in part of the quarry during WW2 nothing remains of this.
Also a underground factory was also set up in part of the quarry, this was due to the Germans bombing Filton Airfield in Bristol thus hampering production for the Bristol Aircraft Corporation a canteen was also built.
It was this section of the Tunnels that, in 1943, was graced with the attractive murals painted by Olga Lehmann to brighten up the otherwise drab and gloomy working conditions.
Ammunition Trains would enter the complex Via a smaller tunnel next to the Eastern Portal of Box Tunnel on the Great Western Main line.
In late 1940 a 18-inch howitzer was mounted on a railway mounting nicknamed “Boche Buster” which had been used in World War I to carry a 14-inch gun . It was deployed at Bishopsbourne in Kent on the Elham to Canterbury Line as a coast defence gun as a precaution against possible German invasion. The gun’s range was insufficient for cross-Channel firing and hence it was never fired in action. This Gun was stored at CAD Corsham along with its 1.5 ton shells during WW2.
After the War the Ammo Depot was emptied, this took a couple of years and the Factory was also closed, but a new threat was emerging the USSR the Cold War had begun and Nuclear War was a real possibility the UK government need a safe place to continue their work in the event of a nuclear strike by the Eastern Bloc. Construction began in the late 1950s however it became outdated shortly after it was built, due to intercontinental ballistic missiles being able to target it.
With over 60 miles (97 km) of roads, the site was designed to accommodate not only the Prime Minister, Harold Macmillan, but also the entire Cabinet Office, civil servants, and an army of domestic support staff, 4000 people in total.
To maintain the secrecy of the site, even during the countdown to war, it was envisaged that 4,000 essential workers would assemble at an outlying destination known as Check Point. Warminster fulfilled this function, and from there a fleet of army lorries would have transported staff to the CGWHQ site. About 210 senior Whitehall officials and their staff, similarly unaware of their destination, were to assemble at Kensington (Olympia) station on the West London Line, before setting off by special train for Warminster, changing there for a short trip by motor bus to Warminster Infantry Training Centre. There they would be broken up into small groups to conclude their journey with a 23-mile (37 km) lorry trip. The Prime Minister was to remain at Downing Street until the last moment, before being transported to Corsham by helicopter.
Blast-proof and completely self-sufficient, the complex could accommodate up to 4,000 people in complete isolation from the outside world for up to three months. The underground city was equipped with all the facilities needed to survive, from hospitals, canteens, kitchens and laundries to storerooms for supplies, accommodation areas and offices. An underground lake and treatment plant could provide all the drinking water needed, and twelve huge tanks could store the fuel required to keep the four massive generators in the underground power station running for up to three months. And unlike most urban cities above ground, the air within the complex could also be kept at a constant humidity and heated to around 20 °C (68 °F).
It was also equipped with the second largest telephone exchange in Britain, a BBC studio from which the PM could address the nation, and an internal Lamson Tube system that could relay messages, using compressed air, throughout the complex.
This was an amazing place to visit so much history in one place.
Sadly the Underground tunnels are unused now but provide a gateway to the past. It is strictly off limits due to the possible dangers of cave ins and is monitored by cameras, unlawful access will be dealt with quite harshly by the MOD.