| Summary : RAF Chilmark, also known as No 11 Maintenance Unit, was an armament depot opened in 1937. It closed as a depot in 1994, with further disposal of much of the ordnance undertaken until 1997. It is situated at Chilmark Quarry, which has been a stone quarry since the 9th century - part of the stone quarry to the north continues in separate civilian ownership (see record 1466497). The armaments depot comprised both underground storage and dispersed surface stores, some linked by a narrow gauge railway. During the Second World War armaments stored here included chemical weapons. By 1965 it was the Royal Air Force's only ammunition supply depot. From the 1960s the depot also handled packed petroleum, oil and lubricants. Some of the buildings and structures still extant when visited in March 2011 included the rail terminus to the south; a gunpost in the eastern entrance area, a gas decontamination building, ablution block and police/guard house; a further guard house, magazines and pyrotechnic stores in the main magazine complex. There is also a former burning ground separated from the main magazine; and separate munitions stores at Moses Wood. Remediation work after closure of the depot included sealing or filling of some of the subterranean storage elements and shelters. Part of the site is managed as a Site of Special Scientific Interest, and it lies within the Cranborne Chase and West Wiltshire Downs Area of Outstanding Natural Beauty. The site continues to be owned by the Ministry of Defence but is understood to be considered for disposal at the time of recording in 2011. |
More information : Quarry from the medieval period, with associated woodland, after 1936 developed as a bomb and ammunition store for the RAF.
This survives as a coherent and rare survival of a late 1930s RAF munitions store and handling facility, extending from the rail-head complex to the laboratory complex, decontamination building, police housing, guardhouse and the magazine/stores complex and associated burning ground. Part of the site is managed as a SSSI and designated as ancient woodland. The laboratory complex includes buildings were built to a high standard in a blend of neo-Georgian/ Modern.
Chilmark quarry's Portland and Purbeck Beds developed from the medieval period for the supply of stone to Salisbury Cathedral and a wide range of domestic and ecclesiastical architecture in the area. It was often, for example, used in a chequered pattern with knapped flint. This is one of 25 quarry sites that were developed in the inter-war period for the storage of ammunition for the army, navy and air force. Prior to that the only buildings marked on OS maps are an engine house and other structures serving the quarries.
During the mid-1930s as the Air Ministry significantly increased its holdings of bombs and ammunition, it sought places suitable for its own dedicated storage facilities, separate from those of the navy and army. In June 1936 (McCamley 1998, 38) it bought the Chilmark quarries, with a view to storing 20,000 tons of explosives. The depot opened in 1937 and comprised underground storage for high explosives - this was not inspected and is in separate ownership as an active quarry, and it is therefore impossible to comment on the potential survival of pre-1940 quarrying remains - and dispersed surface stores, some linked by a narrow gauge railway, for the handling and inspection of explosives, and the storage of incendiaries and pyrotechnics. During the war a wide range of munitions, including chemical weapons, were stored at Chilmark. By 1965, it was the RAF's only ammunition supply depot, and also handled packed Petroleum, Oil and Lubricants (POL). In 1992, a study by the Ministry of Defence's Conventional Armaments Study Team (CAST) proposed moving the RAF's storage to the army's existing deport at Longtown, Cumbria. The rundown of the depot commenced in 1993 and was complete by late 1994 when after a change of plan most of the stock was moved to the Royal Navy depot at Glen Douglas. During this period and until at least 1997 remediation work included explosive ordnance disposal searches, land remediation, and the sealing or filling of caves and air raid shelters (Wooldridge 2005, 62-3).
The site is now divided between:
1.Chilmark Quarry to the north-east, now in separate ownership and in commercial use as a quarry
2.the rail terminus to the south, served by goods sheds and with its own engine house, all in steel-framed construction
3.the continuation of the rail system to serve the laboratory complex for the inspection and handling of explosives, all with small-scale buildings built in brick and tile with stone ashlar detail reflecting an awareness, typical of the period, of the need to soften the impact of large military sites on the environment
4.the eastern entrance zone, with the principal road access through Chicksgrove Wood into open ground (unimproved grassland over spoil) the magazine complex. Key buildings and sites comprise: an overgrown gun post to the north of a single-sex decontamination building (53) for treatment and escape from poison gas, in brick and tile with a boiler stack and an exceptionally well-preserved interior with cubicles and plant; a rendered brick ablutions block (123) and facing south into a looped road in the open ground a semi-detached police house, in brick and tile with a central stack.
5.the main magazine complex, with at the entrance a guard house (54) in brick and tile with ashlar kneelers and portico, sited close to a latrine (87) with gunracks (an unusual feature). Single and some double magazines are set within a landscape with ornamental planting; partly dating from the 1930s, mostly from the 1950-60s - and also some regenerative woodland (eg birch); the road loops around two pyrotechnic stores (35-6) with multiple doors to the south west.
6.the burning ground, with heaps of overgrown ammunition, administrative building, and a small concrete shelter. It is separated from the magazine complex by an ancient routeway which was largely obliterated within RAF Chilmark and has now been reinstated (on a slightly different alignment) as a public bridleway connecting this routeway to north and south
7.Moses Wood, bounded by an ancient bank to coppice stools and with oak standard trees intermixed with some veteran oaks indicative of 18th century or earlier origins. Within the woodland are two munition storage buildings, one with copper vents and the other adapted in the 1950-60s with heat ducting for the storage of missiles.
Assessment of significance (see note 3):
The medieval quarry is sited to the north, and survives as one of the most significant quarry sites in England for its historic interest and biodiversity. It was a source of stone for Salisbury Cathedral and the Houses of Parliament.
The Chilmark complex retains all the components associated with an RAF munitions complex. Individually some structures, such as the decontamination centre, remain in near original condition.
The open ground has been re-landscaped and covered in spill, but the woodland (particularly the banks bounding it) will retain significant evidence for pre-medieval land use and settlement complementing and deepening the understanding gained from Chicksgrove Common. (1)
Additional sources cited in comments above (2-3)
There are a number of images from the Property Services Agency (PSA) Collection housed at the NMR archive in Swindon relating to the Chilmark Depot, these are archive objects P/G 18419/001 to P/G 18419/030. (4)
The National Archives at Kew also hold a number of records on RAF Chilmark relating to its organisation, including maps, plans, photographs and Operations Records Books and visits to the site by the Royal Air Force Staff College. (5)
Aerial photographs taken as part of the Wiltshire Military Disposals project. For more information contact the NMR Archives. (6)
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