RAF Turnhouse Sector Operations Command building

The Barnton quarry military complex is located in west Edinburgh and was built in two distinct phases: the first during the Second World War and the second between 1951 and 1953. The two buildings comprise a Second World War-era Sector Operations Command centre and a Cold War-era R4 ROTOR radar system headquarters, built within two former quarries on the north side of Corstorphine Hill, Edinburgh, and connected by a tunnel.

Second World War Buildings (Early 1940s)

The early 1940s buildings on the site are the southernmost elements of the group. These are the Sector Operations Command centre with an associated ancillary building, likely a power supply building for the site. The buildings were constructed within the disused Barnton Mount Quarry and are made of brick and reinforced concrete with flat concrete roofs. There are minimal openings in the exterior walls, including simple door openings with concrete lintels, with only a few window openings, mostly to the southwest corner where the building connects to the tunnel into the later R4 building. The tunnel is constructed of cast iron segments designed for use on the London Underground. Some of the windows are covered by steel shutters, while others have been sealed.

The interior layouts of the early 1940s buildings are functional, with the main Sector Operations Command building designed around a large central plotting room standing the full two-storey height of the building. There are surrounding office and ancillary rooms on three sides of the plotting room at both ground and first floor level, with a balcony at first floor level also extending around the same sides. There are further rooms to the north, west and south of the plotting room and a central corridor runs north-south through the length of the structure. Most of the interior features have been lost, although some historic elements do remain. These include electrical fixtures and wiring, stair balustrades, doors and much of the paintwork, including painted signage.

Cold War Buildings (1951–53)

The second phase of construction dating to 1951–53 is to the north of the group and comprises a three-storey subterranean R4 ROTOR Sector Operations Centre, the headquarters for the Caledonian Sector of the ROTOR radar system. The building is built within the Barnton Quarry using the 'Cut and Cover' technique, in which a structure is built within an excavated hole that was then buried to create a subterranean space, although in the case of Barnton the quarry itself provided the initial excavation. The hole is lined with a gravel base onto which a reinforced concrete slab was laid. There is a second concrete floor layer laid over a waterproof membrane. The walls of the structure are of reinforced concrete up to three metres thick and waterproofed with bitumen paint. The roof of the overall structure is constructed of concrete cast in steel troughs, with the entire structure then buried under soil. Internally, the walls are constructed of brick and timber, with some timber boarding and cork linings remaining. Surviving internal features include major plant machinery on the lowest level, the cast iron balustrades on the main stairwell, the ventilation ducting and wiring and electrical fixtures and fittings. Interior features such as two of the six main blast doors and most of the telecommunications equipment have been removed from the site in the period since it was decommissioned.

Exclusion

In accordance with Section 1 (4A) of the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997 the following are excluded from the listing: the ancillary power supply and standby set building to the south.

The ancillary building to the south of the main structures is a Second World War power supply building, with a later extension built around 1961 to house the standby set of generator equipment for the facility. The power supply building is part of a common building type, built on a wide range of Second World War sites to a standard pattern, and as a result it is of no significant interest in listing terms. The extension to house the standby set was built to replace an earlier remote standby set house at Barnton Grove and is also not of significant interest in listing terms.

Historical Development

The complex of military buildings at Barnton Quarry were built within a 20-year period encompassing the Second World War and the early Cold War. The first phase of construction was the Sector Operations Command centre. This was developed as a replacement for an existing Sector Operations Command at RAF Turnhouse (now Edinburgh Airport) as part of strategic change to move operational command centres away from sites on the airfields they served. This dispersed arrangement was seen as less vulnerable to attack, as an attack on the airfield would not disrupt the operations of the Sector Operations Command. Operations centres of this type were built across Britain as part of the war effort, and other surviving examples can be seen at Leuchars, Tain and Boyndie.

Following the end of the Second World War and the transition into the early years of the Cold War, the needs of aerial defence also changed. The main danger in the late 1940s was identified as long-range Soviet bombers such as the Tupolev Tu-4, particularly following the Soviet's successful testing of nuclear bombs in 1949. As the British radar capabilities had been reduced following the end of the Second World War, it was insufficient for early warning purposes in the advent of a Soviet attack. As a result, in 1950 development began on a new radar network, codenamed ROTOR.

The ROTOR system made use of a combination of upgraded Second World War radar sites and purpose-built new structures. The system was designed around six air defence sectors, each covering an area of Britain. Within each sector was a mix of Centimetric Early Warning, Chain Home, and Chain Home Extra Low radar sites, providing a broad spectrum of detection. The radar sites would then relay relevant information to the Sector Operations Centre of their sector, where the information would be collated and orders relayed to the Ground Control Intercept stations within the sector, who would then alert the relevant fighter airfields under their control.

Barnton Quarry was selected as the location for the construction of the Sector Operations Centre for the Scottish Sector, designated R4 along with the other Sector Operations Command sites. Building work began in 1951, with most of the construction work completed by the end of 1952, although delays in the supply of telecommunications equipment meant the site was not operational until February 1953.

Even during Barnton's construction, the long-term viability of the ROTOR system was being identified as limited due to rapid advances in technology. These included the development of the Type 80 radar system, although at first this was seen to improve the effectiveness of the ROTOR network, and the development of faster long-range strategic bombers such as the Tupolev Tu-95. These advancements rendered the original design of the ROTOR system officially obsolete by 1956, as it had insufficient range and response time to effectively counter the speed and destructive power now available to the Soviet Union.

Barnton continued in use as the Air Defence Notification Centre North until October 1958, at which time it was downgraded to Care and Maintenance status. It was subsequently transferred to the Scottish Office and refitted internally to serve as the Scottish Central Emergency Government Headquarters, one of fourteen Regional Seats of Government within Britain, part of the civil defence network intended to provide shelter for a regional commissioner to maintain some level of command and control over the relevant area in the event of the central government's destruction during a nuclear attack. It continued in this role until full closure in 1983 and in 1984 was transferred to Lothian Regional Council. While in the council's ownership they considered the site for potential use as an emergency centre, although in the end this did not happen due to a lack of funding for the proposal. In 1987 it was sold into private ownership and fell into dereliction, with fires in 1991 and 1993 damaging the interior of the structure. Since 2011, there has been a planned restoration programme, seeking to restore the bunker to its 1952 layout and open the site as a visitor attraction.