Former RAF Alconbury: Alert Facility Building (Building Number 103)

Security police headquarters building, built in 1977 for the United States Air Force. It was designed by JE Gray, structural engineer to the Public Services Agency, and constructed by George Wimpey Limited.

MATERIALS: of reinforced concrete with red facing bricks to the first-floor (excluding the blast valve penthouses).

PLAN: the building is rectangular on plan, aligned roughly east to west, with the blast valves housed in two separate penthouses at the west end.

EXTERIOR: the ground floor is concealed on all four sides by a grassed earthen berm which is cut through at the south-west corner by revetment walls to accommodate a service road. A flat-roofed entrance passage projects at the north-east corner.

On the first floor, the left-hand section of the southern elevation is of painted reinforced concrete and consists of blast valve penthouses. It has four rectangular openings, two with original louvered ventilation grilles and two with replacement ventilation grilles. The remainder of the elevation is of stretcher bond red brick and is blind except for an off-centre left doorway concealed behind a blast wall. The rear elevation is also blind and has an emergency exit shaft enclosed by railings to the off-centre left. To the right, the rear blast valve penthouse is recessed and has three rectangular openings, two with original louvered ventilation grilles and one with replacement ventilation grilles.

INTERIOR: the ground-floor entrance passageway leads to a stairwell with an open-string concrete staircase with square-section metal balusters and moulded handrail. On the ground-floor stairwell wall there is a wall painting depicting the seal of the United States Department of the Air Force.

On the first floor the original room layout of a gun mount room, weapons equipment room, ammunitions store and toilets still survives, all with their original steel doors. In the wall between the weapons equipment room and gun mount room there are three steel-meshed service hatches with steel security doors with spy holes. The guard mount contains a pair of wooden clearing barrels, safety devices designed to capture a discharged round, and the ammunition store contains an ammunition cupboard along with a wall painting depicting the head of a bald eagle.

The ground floor is believed to still retain its original room layout. This includes offices for a weapons security officer, and Flight Chief, along with clean and dirty plant rooms.

Below the ground floor there is a set of three-bay underground chambers, one containing a steel oil tank and one a steel effluent tank, while the third, which is beneath the clean plant room, is a concrete chamber for storing cold water.