This Cold War bunker, used for monitoring the movement of radioactive fallout in the event of a nuclear attack on the UK, is probably not much known to many locals. Situated on a hillock, overlooking Heron Hill and the Castle Estate, it consists of nothing more than a green concrete 'box' protruding above the surrounding grass.
The bunker was inspected as part of the Defence of Britain survey between 1995 and 2002, and was found to be in good condition. It was opened in March 1963, and closed in September 1991.
Check out the following link for some great close up and interior photos:
Days Later link 1
Days Later link 2