Monument record 2943/1/0 - Hack Green R6 GCI Rotor Bunker

This was a Ground Control Intercept Rotor site and the main building was an R6 Semi Sunken Bunker (2). It had a total of eight 'Radar Heads' recorded in December 1953; one 7 Mk 2; one 14 Mk 9; one 14 Mk 8, two 13 Mk 6 and three 13 Mk 7 (1). It was later converted into the Regional Headquarters (CSMR: 2943/0/0) in the 1980's. It probably replaced the World War two radar station (CSMR: 4069/0/5) at SJ65414688.
Rotor sites such as this were constructed as part of an effort to build an effective radar network across Britain following the War and were give equal priority to the development of Nuclear weapons and guided missiles.
The bunker was semi sunken, likely built on a bed of gravel over four inches thick, with a concrete mattress six inches thick on top of this. On top of this the base of the bunker will have been cast, which will have been ten foot thick and re-enforced with a waterproof layer spread over it. The outer walls and roof will also have been ten foot thick, while the internal walls were six inches thick. All of this will have been coated in an asphalt damp course and then a six inch thick brick wall built around it; and internal walls in rooms that will contain equipment would have been lined with cork.
The bunker has a central corridor, offset to one side. The main rooms were on the wider side while the narrower side contained the rest rooms, lavatories, duty offices, and air conditioning plant and telecommunications apparatus. The floor of the bunker was raised so that cabling and air conditioning could be run underneath.
The bunker was entered by a doglegged passageway that was designed to lessen the impact of a blast wave on the relatively weak inner door. The bunker also had a rear emergency exit that was similar to the main entrance and was also doglegged.
The radar system based here was quickly out developed as better radar systems and better Soviet jamming systems came into operations, as this system was little more than modified World War two technology; however the site was continually updated, even sharing the bunker with civil aircraft control in the 1960s (2).
The site does not appear to have been abandoned at any point before being turned into an Regional Government Headquarters (see CSMR: 2943/0/0).

<1> C S Dobinson, 2000, Twentieth Century Fortifications in England: Volume XI 2 - The Cold War (Report). SCH4456.

<2> W D Cocroft and R J C Thomas, 2003, Cold War - Building for Nuclear Confrontation 1946 - 1989 (Book). SCH4466.