Between 1955 and 1991, more than 1,500 of these underground facilities were located right across the UK, roughly 10 miles apart mainly in remote rural locations. They were of a standard design and constructed of 12 inch thick, steel-reinforced concrete 20 feet beneath the ground.
In the event of a nuclear attack, these posts would have been manned by three members of the Royal Observer Corps (ROC). Their role would be to note the details of a nuclear burst and relay this information to UKWMO headquarters. This information would then be used by government and local authorities in order to decide how best to protect civilian life.
These bunkers had no mains water, electricity, gas, or heating. The only communication with the outside world was by way of a simple Tele-Talk system to headquarters and 3 to 4 other nearby ROC posts in the ‘cluster group’. The master post in each cluster group was the only post to be equipped with radio communications as a back-up.