R4 three-level Sector Operations Centre bunker built as part of the ROTOR programme. A fourth floor was later added and the bunker became SRHQ4.1 and later RGHQ4.1
Site was closed and stripped out in 1992. Now owned by Highpoint Communications, who use it as a radio site. They do not use the bunker, and visits are discouraged.
When Linesman was in the offing it was proposed to dig another hole about half way along the access tunnel and insert a second R4 which would have housed the Linesman system. The project was costed and surveyed and approved, but never happened due to the alarming computer failures of Linesman itself. Had it gone ahead, this would have been one of the most unique bunker sites in the UK, sporting two R4s side by side.