The Regional General Headquarters located at RAF Chilmark, Wiltshire, date back to the early 1980’s when the Home Office initiated plans to replace the Sub-Regional Control bunkers in the southwest region. Plans were drawn up to decommission and replace both the RGHQ 7.1 near Ullenwood, Gloucester, and RGHQ 7.2 located in the converted ROTOR R6 RSG at Hope Cove. In 1982, a design for the new bunker was prepared and construction was started in earnest in 1985, being completed within three years. RGHQ Chilmark was designed as a two-level bunker, approximately 200 feet in length and forty feet wide. The bunker was located on gently sloping ground overlooking the Nadder Valley near the village of Chilmark, it is located on MoD land next to the rail interchange sidings of the vast RAF Chilmark underground bomb store.
For reasons unknown, the new Home Office bunker did not take advantage of the existing disused subterranean bomb store located within the confines of RAF Chilmark. Instead, a hillside was excavated down to the bedrock and a plateau was formed to create the foundations of the bunker. A concrete box with two foot thick reinforced walls formed; once the construction was completed, the excavated earth was backfilled over the bunker to a minimum depth of ten feet. After the bunker was buried, there was little evidence above ground other than a series of prominent ventilation stacks on the hilltop above the bunker, and a pair of inclined entrance shafts into the hillside. The bunker was laid out so that the lower floor is dedicated to office accommodation and operational areas. and the upper floor, which is marginally less well protected against blast and heat, contains the headquarters’ dormitories and welfare facilities. Almost one third of the bunker is given over to service installations such as standby generators, power distribution cubicles and air-conditioning plant.
With the collapse of the Soviet union in 1992, RGHQ Chilmark was wound down and put into care and maintenance, being operational for only a small number of years. The bunker was sold to a private individual sometime after closure, who has since sold the bunker on to another party. An on going police investigation is underway into the bunkers use as a cannabis farm.