On the North side of a footpath, 50 yards West of A41. West of lay-by by footbridge on Northbound carriageway, half a mile North of junction 20 of M25.
OPEN All surface features remain intact. A metal dome on the ventilation shaft indicates this was a master post. The hatch was open when first inspected but was later welded shut. A further inspection on 25.8.2001 revealed the hatch open but the shaft filled with rubble. Internally there is some fire and smoke damage and vandalism but much still remains including twin bunks and single bed, folding table and shelf, cupboard, some BT equipment, wiring, papers, copper strap round the top of the walls. The walls are covered with polystyrene tiles. There is an unusual wire filter on the underside of the FSM pipe. A wooden sign ‘Kings Langley ROC Post’ has been removed for preservation.
Opened in 1959 and closed in 1991.