NS4079 : Royal Observer Corps Monitoring Post, Alexandria
taken 13 years ago, near to Jamestown, West Dunbartonshire, Scotland

In the present view, the access shaft is clearly visible: NS4079 : Alexandria ROC Bunker: access shaft. On its near left is a small mushroom-like object, which was the mount for the Ground Zero Indicator: NS4079 : Alexandria ROC Bunker: GZI mount. The part of the structure directly below that mount was a ventilation shaft, and on both sides of that shaft are openings which would originally have held louvred covers.
The area of housing in the background is in Renton. A large building visible on the right is the NS3979 : Vale of Leven Academy.
This ROC monitoring post — see Link and Link for a detailed description of these Cold War relics — was a master post. It is set in a field, on a west-facing slope, just downhill from a small square of woodland that contains the ruins of Northfield Cottage. At the foot of the slope is Northfield Road and the Dalmonach estate.
The Royal Observer corps was a civil defence organisation operating in the United Kingdom between 29 October 1925 and 31 December 1995.
During the cold war ROC monitoring posts were developed for monitoring fallout and radiation in the event of a nuclear attack. The operators hidden below would occasionally emerge to collected photographic film from a 4-axis parabolic camera mounted near the hatch, retreating below ground to develop it. A patch of darkening might have indicated the direction of an explosion. Once centally collated these observations would triangulate the site of an attack.
A variety of instruments would detect radiation and fallout levels, and the bunker itself used the earth to protect the volunteer observers, who had telephone and radio communications up the chain of command.
There were 1,563 of these posts constructed and one of the specialist groups researching the history of the ROC has mapped them all. See Link(there is a great deal of detailed information about the posts on the rest of that site)
See Linkfor background and a reconstruction of a working observation post.
There is a good history of the ROC on wikipedia at Linkand a charitable association for the welfare of the former volunteers at Link
