On top of Warren Hill on the South side of A474.
OPEN All surface features have been removed apart from the BPI & FSM pipes which still stick out of the ground. There is no trace of the ventilation shaft but the access shaft is still open at ground level but a long concrete slab and the top of the ventilation shaft have been forced behind the ladder pushing it against the opposite wall. Thin people could probably still get in.
A circular rubble filled pit a few yards to the East could be part of the aircraft post, or a WW2 gun emplacement or something else.
Opened in 1964 and closed in 1968.