Monument record 2942 - Frodsham Anti Aircraft Operations Room (The Beacons)

<1> W.D.Cocroft, 2001, Cold War Monuments: an assessment by the Monuments Protection Programme (Report). SCH4336.

The bunker at Frodsham is in a good condition, retaining many of the features that make it of national importance (original internal layout, standby generators, air conditioning plants and ducts).

The ‘Beacons’ is the only identified example of an above ground AAOR; all other known examples are semi-sunken. Internally it retains its original room configuration, including the open central operations room overlooked by curved Perspex panels of the control rooms. Also surviving is much of its original standby generator plant and air conditioning system. This AAOR also controlled the 1950’s Anti Aircraft Battery at Norley (which has also been recommended for protection) which illustrates the dispersed nature of the components of the early 1950’s air defence system. The bunker remains in use by Cheshire County Council and has been considered for listing in 2001.

There were 32 AAORs in Britain. 23 of these were in England, three in existing building and 20 purpose-built of which 12 are known to still exist varying in condition and 2 which have been demolished. The gun-defended areas were placed by major conurbations and centres of armament production. The AAORs were intended to receive information of the approach of hostile aircraft from the Master Radar Stations they would then allocate targets to the gun batteries within the area. This function of receiving, analysing and communicating information is clearly reflected in their internal architecture consisting of a central operations room surrounded by control cabins.

<2> English Heritage/DCMS, Various, Notification of inclusion, amendment or removal from the List of Buildings of Special Architectural or Historic Interest, Ref: 475274 Lipscombe D 18/03/2013 (Written Communication). SCH4885.

The former Anti-Aircraft Operations Room (AAOR) at Beacon Hill, Frodsham was one of twenty-eight purpose-built examples constructed for the Royal Artillery between 1950 and 1951. It was under the command of 4 Group, 79 Brigade and controlled the gun sites in the Mersey Gun Defended Area. The operations room received long-range radar reports of the approach of hostile aircraft from the RAF’s Master Radar Stations. A trial Yellow Yeoman (Type 82) tactical control radar associated with the AAOR would then pick up and track the targets before they were allocated to the automated gun sites within their GDA.

Their role was short lived, and following the abolition of Anti-Aircraft Command in 1956, the bunker was acquired by Cheshire County Council in 1961 which converted it into a Civil Defence Training Centre. This new use was also short lived as the Civil Defence Corps was disbanded seven years later in 1968. Having stood empty for some time, the building was refurbished in 1986/87 and became the Cheshire County Standby Emergency Centre and the Cheshire Fire Brigade County Standby Control Centre; the main control being at Winsford.

An Anti-Aircraft Operations Room built c1951 for the Ministry of Defence to a design drawn up by the Ministry of Works. It is built of reinforced concrete, fitted with steel blast doors and ventilators. 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.

Since the building was designed to resist the effects of a nuclear explosion, 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 south-east elevation is at ground level, while a second entrance in the north-west elevation is at the upper-floor level and is approached by a flight of concrete steps set into the slope of the hill. The two entrances have double steel blast-doors that are protected by open-sided concrete blast wall porches. Three round, steel ventilator grilles protected by plain projecting concrete drip moulds are situated to either side of the entrance in the north-west elevation.

The building is entered at the lower-floor level in the south-east 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 bar 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, Other Ranks (OR) and Women’s Royal Army Corps (WRAC) 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 the northern and southern sides are occupied by cabins which retain their curving anti-reflection Perspex windows. The blank south-eastern wall would originally have had situation tote and map boards displayed on it.

The upper floor corridor is accessed externally from the north-west entrance, doorway and internally from the lower floor by a total of five stairways protected by painted galvanised tube and steel mesh balustrades. As with the lower-floor, a series of rooms surround the operations room; including latrines, rest rooms, a NAFFI, civil servants’ room, switchboard, and various offices. Some of the original partition walls have subsequently been removed and an open dining area occupies most of the south-western side of the upper floor, while the former WRAC latrines have been converted to a kitchen. The original positions of walls are visible as witness marks on the Marley-tiled concrete floors. Most of the rooms on both floors retain their original plain wooden doors; the original box ducting for the ventilation system remains intact throughout. The original air conditioning plant and filtration system is intact, although the boiler and the stand-by generator have both been replaced by modern equipment.

<3> W D Cocroft and R J C Thomas, 2003, Cold War - Building for Nuclear Confrontation 1946 - 1989, p.148-50 and p.153 (Book). SCH4466.

In the 1950s the army retained responsibility for anti aircraft defences, which were divided into thirty three gun defended areas. Frodsham was the command centre for the Mersey Gun Defended Area. In most cases the Anti-Aircraft Operations Room were purpose built monolithic reinforced concrete bunkers costing between £20,000 and £35,000. At Frodsham the building has been built into the hillside for extra protection. The heart of the building is a double storey plotting room overlooked by a viewing gallery and control cabins, surrounded by equipment and rest rooms. The Anti-Aircraft Operations Room was typically some distance from their gun sites. Trail were undertaken at Frodsham for a new tactical fire control radar, but no associated infrastructure has been identified. Includes plan and cross section.

<4> Cheshire West and Chester, 2012, Floor Plan of the Cheshire County Standby Emergency Centre (Graphic Material). SCH7315.

<5> Various, Various, Oral communication to the HER, Edwards R 14/01/2014 (Oral Communication). SCH2330.

The building is now used as a file store.

<6> Royal Commission on the Historical Monuments of England (RCHME), 1990's, RCHME Cold War Project, Wayne D Cocroft/23-SEP-1997/RCHME Cold War Project (RCHME Research Project). SCH8045.

SJ 5199 7660. The Beacons is an Emergency Planning Centre operated by Cheshire County Council. It occupies a double storey reinforced concrete bunker built about 1950 to house an Anti-Aicraft Operations Room (AAOR). It was built to control the newly established automated anti-aircraft gun sites in the Merseyside region. This role ceased in 1955 when the army relinquished responsibility for air defence.

Technically, the site at Frodsham is notable for the installation of the prototype Orange Yeoman tactical control radar in the mid 1950s. Although the AAOR ceased operation in 1955 this radar remained in place for training purposes until 1959 when it was relocated. Soon afterwards the bunker was taken over by Cheshire County Council for use as an Emergency Planning Centre. It retains this role and is in good structural condition.