Lippitts Hill: Anti-Aircraft Operations Room (Bunker)

An Anti-Aircraft Operations Room built around 1951 for the War Office to a design drawn up by the Ministry of Works.

Materials: it is built of reinforced concrete, fitted with steel blast doors and ventilators

Plan: it is square in plan and comprises a two-storey semi-sunken reinforced concrete structure with a central operations/plotting room surrounded on both floors by a circulating corridor, with control cabins, offices, communications rooms, plant rooms, latrines and dormitories.

Exterior: since the building was designed to resist the effects of a blast, (one of the effects of nuclear explosion, but might also have been built to resist the effects from conventional bombs too) there are no windows and the only openings in the structure are the two entrances, ventilator grilles, the stand-by generator exhaust and a protruding ventilation flue on the roof above the plant rooms. The main entrance situated centrally in the north-west elevation is at ground level, as is the second entrance in the south-east elevation. The two entrances have double steel blast-doors that are protected by open-sided concrete blast wall porches.

Interior: it is entered at the upper-floor level in the north-west elevation and the entrance leads into a lobby that functioned as the reception/security room. A dog-leg circulatory corridor gives access to a number of rooms built around the centrally positioned full height former operations room. All of these rooms, except the boiler, air conditioning, and generator rooms have been given different functions over time; their original functions included the tactical radar control room, radio-telephony room, telephone-frame room, and rest rooms. The well of the operations room is entered from the circulatory corridor by two doorways on opposing sides of the room. It is overlooked by viewing galleries at first floor level, supported on plain tubular steel columns. The galleries are accessed from the upper floor, and on both sides are work stations which retain their curving anti-reflection Perspex windows. The blank wall retains a full width blackboard which originally had situation tote and map boards displayed on it.

The upper floor corridor is accessed externally from both the north-west and south-east entrances, and internally from the lower floor by a number of stairways. As with the lower-floor, a series of rooms surround the operations room; these are likely to include latrines, rest rooms, a NAFFI, civil servants’ room, switchboard, and various offices. Due to the nature of its current use as a secure store, access was not possible to all areas but it appears that most of the rooms on both floors retain their original plain wooden doors, timber framed internal hatches and kiosk window within the reception area. The original box ducting for the ventilation system remains intact throughout. The original air conditioning plant and filtration system also appears to be intact.