Fort Halstead: Buildings F16 and F17

The Fort Halstead site is located on a prominent hilltop, which is part of the North Downs, to the north-west of the village of Dunton Green. The site includes both the late C19 Mobilisation Centre ('Fort Halstead’) in the south of the site and a large number of buildings associated with the research facility to the north and north-east of the fort. Buildings F16 and F17 lie within the fort.

BOMB CHAMBER (BUILDING F16) A reinforced rectangular concrete structure for the detonation of explosive devices with an E-shaped single armoured chamber. An external metal staircase attached to the south-east elevation provides access to the flat roof which has metal railings to the rear (north-east elevation) and sides (south-east and north-west elevations). The rear and side elevations have three horizontal rows of square metal plates with central bolts which are presumed to be fixings for the monitoring of any detonations. There are also electrical inlets and outlets in the rear elevation.

DETONATION CHAMBER (BUILDING F17) A bi-partite building of reinforced concrete and brick. To the south and west it is a single storey flat roofed structure housing the armoured laboratory (in reinforced concrete); to the south and east it is faced in red brick English bond, but the north elevation is in concrete (the west elevation was not inspected). The laboratory has a large and prominent T-shaped funnel to its flat roof. The main access is via folding wooden doors in the east elevation. A porch has been added to protect a south pedestrian doorway. At its north-east corner the building rises to two storeys, again in red brick English bond. All windows are metal-framed casements with concrete heads.

The interior was not inspected but it is known that the bursting chamber is located in the single storey part of the building. It is divided into two parts described as ‘large’ and ‘small’ on original plans. Each section has armoured glass observation windows and the whole is flanked by camera rooms to either side. Explosions were recorded using an angled mirror and a high speed camera. The two-storey ‘tower’ housed a photographic dark room on the ground floor and a control room above from which the trials were overseen.