Combined Task Force 345 Nuclear Attack Proof Bunker – is Great Britain's secret nuclear bunker buried 100ft down, built into a hillside is in the leafy London suburb of Northwood.    Inside is the control room where the order to launch a strike would be given from the Secret Operations Room which controls the submarines that carry our nuclear deterrent.   The bunker is permanently manned by watch keepers on 12 hour shifts.    Work on the bunker began in 1941 when RAF Coastal Command were based there, and it has grown over the years to become a network of six underground buildings joined together with temperature and humidity controlled, and the air below ground is over pressured so that in the event of a chemical attack outside, no toxic gases would be sucked in.