Paddock is the codename for a back-up secret cabinet war room bunker built during WW2 should Whitehall be no longer viable.
The bunker complex was constructed in total secrecy in 1939 in Dollis Hill, underneath part of the Post Office Research Station site.
Paddock is designed to be a virtually bomb proof bunker, built on two floors and containing forty rooms to house all branches of the military and primary assets of the government.
Despite costing around £250,000 (a massive sum for WW2), Paddock only saw two meetings by the cabinet as Churchill found the damp and hot conditions rather unsettling.
Paddock is now managed by a housing group that runs the occasional open days for the public, but remains closed most of the year.