This underground headquarters bunker, with a surface element, was built in 1960 for No. 1 Group of the Royal Observer Corps. The role of the Group HQ was to receive and process reports of the location and strength of nuclear bursts and the spread of radioactive fallout from such posts across its area of responsibility (Kent and the eastern parts of Surrey and Sussex). Scientific advisers in the bunker examined information about nuclear bursts and predicted the spread of fallout. This information was communicated to the controls of armed services, and other recipients in a communications chain. Local communities could be warned of approaching radiation through the use of air raid sirens or maroons. The safest routes for the traffic of military vehicles and of the emergency services could be established as well as information collected about which airfields were at risk or, at the time, unusable from the spread of fallout.