Project ROTOR
Nice house eh? it doesent look like the entrance to a secret underground radar station does it? but neither do any of it's identical relatives! they all have 100-150 feet long underground tunnels leading to 1-3 storey underground complexes. they were all built in the late 1950's to house top secret radar installations called project 'rotor' however,when ROTOR became obsolete, they were wound down with a lot of them ending up as regional control centers or RSG's to be used in the event of a nuclear war.

Dotted up and down the length of the east coast of Britain many of these places remain today but in a bad state of disrepair. The west coast had similar stations, but usually above ground bunkers.

Project Rotor was a Top Secret radar network designed to cover all of Britains airspace, using the type 80 radar system developed after WW2. they were all linked and in constant contact with each other. 
Anstruther. The Scottish Command.
at one time the most important ops base. 
now a museum! click here for website!
Sub-Brit
Inverbervie ROTOR station pictured below, this origionally had only one underground level but was later expanded by the addition of another level below the origional one whilst in use by the American navy, where they had their oceanographic monitoring station from the '60s up until 1978