RAF Fighter Command, 12 Group HQ, Nottinghamshire
Flooded underground Entrance No2 to the former control room at what was once RAF Watnall, Nottinghamshire.
At this level, you are some 35ft -40ft below ground, the door ahead being the actual entrance into the control room upper level. This is currently flooded to a depth of about 18" (46cm). we did not venture beyond this point, but I understand that part of the control room floor is wooden, posing extreme danger for anyone who ventured further into the long abandoned complex.
There is a basement below this level at a depth of about 60ft below ground, but this is totally submerged.
Having been constructed in 1941, and until its closure in 1961, the area would have been a top secret establishment, only accessible to authorised personnel. Following its closure, the underground complex was sealed off, however, thieves and vandals broke in during the 1960s, vandalising the interiors and stealing anything of worth including all the copper cabling, and the electric pumps that kept the place free of flood water. The remnants of the cable saddles can be seen on the walls. I'm not sure what the tubes/bar ends are that protrude through the wall are, unless this is part of the structure's reinforcement.
Over the years the rising water table has caused the place to flood extensively, making penetration of the upper level of the subterranean complex extremely dangerous, and the lower level impossible. The water marks on the wall indicate the highest water levels.
Please note that this former RAF facility is on private property and is not open, or accessible to the public; it is also sealed off from the outside world by locked steel doors.
A similar facility exists at Biggin Hill that served Fighter Command 11 Group, which is restored to its WW2 condition and is open to the public.