Royal Observer Corps (ROC) monitoring post

ROC and UKWMO monitoring post, to a standard design of 1956 by the Air Ministry Works Department and built between 1958 and 1961.

MATERIALS: reinforced concrete with a compacted earth covering.

EXTERIOR: located on the south-west boundary of Dunsfold airfield it appears as a rectangular, flat topped, vegetation covered mound with a raised entrance shaft towards one end and a smaller, raised air vent towards the other end. The concrete entrance shaft has a counterweighted steel hatch and adjacent to it are metal ventilation louvres and the metal fitting for the Ground Zero Indicator (a pinhole camera device for detecting the direction and altitude of nuclear explosions). A stepped brick mounting block adjoins the shaft.

INTERIOR: the 4.6m deep vertical entrance shaft is 0.6m square with a steel access ladder. At the foot of the shaft is a drainage sump with a metal grill. The sump retains its wall-mounted rotary hand pump. The shaft gives access via two timber doors to a small closet for a chemical toilet and to the monitoring room which measures 4.6m by 2.3m. The walls and ceiling of the monitoring room are clad with textured polystyrene tiles (probably a later addition to attempt a degree of insulation). The room retains its rubberised flooring. Along one wall are two crude fitted wooden tables, either side of a cupboard, and some fitted shelves. The walls retain the metal and plastic trunking and, at the far end, a metal ventilation flue shutter. The fittings remain for the fixed survey meter probe (which allowed the recording of external gamma radiation without venturing outside) and the bomb power indicator (which measured the size of a nuclear explosion).