Summary
Two adjacent rooms contained within a former Bath stone quarry, latterly adapted to an underground government facility: Central Government War Headquarters (CGWHQ); fitted for use as a radio studio.
Reasons for Designation
The Radio Studio in the CGWHQ, below MoD Corsham is designated as a Scheduled Monument for the following principal reasons:
* Period: the peril from the threat of nuclear strike that Britain faced during the Cold War is inherent in the need to provide this facility to broadcast information following a nuclear strike.
* Rarity: the site itself is unique, and this is one of only two Cold War underground radio studios to survive intact.
* Survival: the rooms retain their soundproofing and I/O tie-line (communication cable) as fitted.
* Group Value: the CGWHQ site is an unparalleled example of our national Cold War defence heritage, and represents the systematic use of expansive underground areas by industry and the military during the C20.
* Representative: the sober fitting out of the Bath Stone chamber, with breeze block partition and window, is redolent of the grim character of the Cold War era and the functional nature of the area.
History
The Corsham Mines are a multi-layered historic site near Bath, beneath the southern end of the Cotswold Hills in Wiltshire. Quarrying of Bath Stone in the wider area took place from Roman times, and by the C18 Bath Stone had become a highly sought after building material. The opening of the Kennet and Avon canal in 1810, and the subsequent construction of the Great Western Railway in the 1840s, made the transportation of the stone to farther locations easier and cheaper, thereby increasing its popularity. Brunel's cutting of the Box Railway Tunnel, beside the village of Corsham, revealed a rich seam of high quality stone beneath the hills. Intense quarrying followed, leaving a network of quarries with worked-out chambers and air shafts, including Spring Quarry. By the time mining ceased in 1940, there were over 60 miles of tunnels across 3,000 acres, located at depths between 80 and 100 feet below ground.
The Bristol Aeroplane Company (BAC) at Filton, near Bristol was bombed in September 1940. In response, Lord Beaverbrook, of the Ministry of Aircraft Production (MAP), issued an urgent plan to relocate all production below ground, which was endorsed by Churchill. The limitations of time, suitable sites, and wartime resources quickly saw the scheme scaled back to the relocation of Filton's engine plant. In December 1940 four quarries were requisitioned by the Ministry, including Spring Quarry, to the south of the Box Tunnel. It covers a vast 3,300,000 square foot area (or 76 acres). It was intended that BAC would convert Spring Quarry for engine production in 6 months, at an estimated cost of £100,000.
However, the scale of the Ministry's factory construction project was enormous, involving the removal of thousands of tons of rubble stone, the levelling of floors, and the strengthening of pillars and roofs using steel and concrete. Lifts, escalators, and an extensive ventilation system were installed. Furthermore, BAC became doubtful about the practicality of the project, and their involvement was scaled back. The factory was not ready for use by the end of 1942, when German bombing had largely ceased, and the need for the underground factory programme had all but vanished. The MAP factory was reclassified as a shadow factory, and proposed production was switched from the Hercules engine to the less vital Centaurus. By 1945, the factory still fell short of its original specifications, and its cost had risen to many millions. Throughout the war, engine production figures were negligible and the factory closed at the end of the war. MAP itself was abolished in 1946. Spring Quarry was bought by the government in 1954, when the north-east area was allocated for conversion to a secret CGWHQ for use in the event of nuclear conflict.
The first known planning for the dispersed operation of government departments, should Central London be destroyed through enemy attack, was during a sub-committee of the Committee of Imperial Defence under Sir Warren Fisher in 1937. Following the war, it was acknowledged that developments in weapons meant that the government's emergency plans were inadequate. In the light of the huge sums spent developing the MAP factory in Spring Quarry, estimated at £30 million, the Treasury proposed buying the requisitioned quarry for use as a citadel for future emergencies. However, the quarry was not bought from the Bath & Portland Stone Company until April 1954, along with 100 acres of land above ground. In 1957 the plans for the emergency headquarters were finalized; the site was intended to provide a safe haven from which the work of Government could continue. From here, the reconstruction of the country following a nuclear attack would be overseen. It was designed to accommodate up to 4,000 military and government staff, including the Prime Minister and key cabinet officials. Occupants would be sealed underground for 30 days and coordinate with Regional Seats of Government around the country, meaning that extensive communications and welfare infrastructure was needed.
Work began in 1957 with the construction of a reinforced concrete wall separating the CGWHQ area from that part of Spring Quarry used by the Admiralty. A buffer zone between the two was lined by a concrete block partition and solid rock pillars, sealing the Central Government side. Three blast doors were installed. New ventilation shafts were created and reinforced. Internal areas were divided by concrete block or, in some cases, with red brick. The northern parts of the main roadway through Spring Quarry (now called East/ West Main Road) were converted to a large telephone exchange, stores and plant rooms. Those to the south were offices and accommodation for the Government departments and War Cabinet, a communication centre, and an extensive canteen and kitchen facility. Most of the major building works were complete by April 1959. By 1961 the radio studio had been installed with soundproofing, and has remained unused since its installation. In the event of a nuclear attack, the Prime Minister would have broadcast to the world from the studio, via the BBC's emergency centre at Wood Norton.
The CGWHQ complex was never needed or used for its intended function, and was reduced in capacity over a number of phases during the late C20. The site was de-commissioned in the early 1990s. It was de-classified in 2004.
Details
PRINCIPAL ELEMENTS: two adjacent rooms designed as a radio studio and technician's control room, with soundproofing attached to the walls and ceilings, and a window inserted within the shared wall.
DESCRIPTION: part of the underground complex at Corsham. The room to the west, the Studio, is approximately 4m square. The room to the east, the Office, is approximately 4.4m x 3.7m. Both rooms are constructed of concrete block within the quarry. A concrete step leads into the doorway of the Office. The Studio has a small internal lobby constructed of timber. The rooms are divided by a concrete block wall with a central window in a timber window frame. Suspended ceilings have been inserted and lined with sound-proofing, which is also attached to the walls of both rooms. The sound-proofing comprises square hardboard sheets with slits, framed in timber and fixed with metal hinges. The rooms are fitted with an I/O tie-line (with a modern interface connector in the Office), a communication cable for broadcast use.
The scheduling only includes the below-ground features noted. All surface buildings and structures are excluded from the monument. The scheduled area includes a 1m margin on all sides as well as above and below. However, the floors and ceilings in the passageway outside are excluded to accommodate any future need to install services.
