Ancient Monuments

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Anti-aircraft site at Searson's Farm, Trimley St Mary

A Scheduled Monument in Trimley St. Mary, Suffolk

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Latitude: 51.9771 / 51°58'37"N

Longitude: 1.3134 / 1°18'48"E

OS Eastings: 627656.764539

OS Northings: 236145.955168

OS Grid: TM276361

Mapcode National: GBR WRQ.2WG

Mapcode Global: VHLC8.QK6P

Entry Name: Anti-aircraft site at Searson's Farm, Trimley St Mary

Scheduled Date: 7 October 2014

Source: Historic England

Source ID: 1420538

County: Suffolk

Civil Parish: Trimley St. Mary

Built-Up Area: Trimley St Mary

Traditional County: Suffolk

Lieutenancy Area (Ceremonial County): Suffolk

Church of England Parish: Trimley St Martin

Church of England Diocese: St.Edmundsbury and Ipswich


A Cold War heavy anti-aircraft gun site comprising four gun emplacements, a generator and gun store building, a Command post and partly ruinous radar tower, and a telephone test hut, constructed in 1946.

Source: Historic England


The monument lies near to the mouth of the Orwell river, on a plateau to the north-west of the port of Felixstowe, and includes the structural remains of a Cold War heavy anti-aircraft site comprising four gun emplacements and associated buildings; the former generator and gun store building, Command post and partly ruinous brick radar tower, and a telephone test hut.

The four gun emplacements are located on concrete spurs which extend from the corners of a roughly square concrete platform measuring 40m east-west and 50m north-south located at TM27643615. The centre of the platform is covered with dumped material. Each circular gun emplacement is approximately 10m in diameter and constructed of reinforced concrete. Although two of the four emplacements are heavily covered with vegetation, all appear to survive well, with a central gun pit approximately 1.5m deep to accommodate the traversing mechanism of the gun and hydraulics of the automatic loading system. Attached to the rear of each gun pit is an engine house which contained a diesel generator, hydraulic pumps and an air compressor to power the recoil system. None of the equipment, mechanisms or pipe work appears to survive.

Approximately 45m to the south-east of the emplacements, on the west side of the track, is the generator house and gun store, a single storey, flat-roofed, reinforced-concrete, L-shaped building with heavy steel-shuttered doors and windows. At the southern end of the building, the gun store has small square apertures near to roof level and steel-louvre ventilation openings. No interior inspection was made. Opposite the generator house, approximately 20m eastwards from the east side of the track, is the telephone test hut, a brick and reinforced concrete structure with a flat roof. Approximately 160m further to the south of the generator house and gun store on the east side of the track lies the Command post, a flat-roofed, reinforced-concrete structure with a steel-shuttered door. To its north-west lie the remains of the brick radar tower and ramp. No interior inspection was made.

The monument includes the gun emplacements, generator building, gun store, command post, radar tower and telephone test hut. The position of the telephone test hut on the map is indicative only. The trackway, although contemporary, is excluded from the scheduling.

Source: Historic England

Reasons for Scheduling

The anti-aircraft battery at Searson’s Farm, Trimley St Mary, constructed in 1946, is scheduled for the following principal reasons:
* Survival: the site retains most of the key components of the Cold War ensemble including the gun emplacements, generator building, gun store and Command Post, and some of original mountings and fittings;
* Historic importance: is an important and evocative witness to the nation’s cultural, economic and military experience during the Cold War, demonstrating the importance of air defence, and its rapid technological enhancement, during the C20;
* Rarity: the ensemble is a rare example of a 5.25 inch calibre battery surviving to such an extent, and retains a ramped, brick radar tower, considered to be a very rare survival indeed;
* Group value: it has historical and functional group value with the Anti-Aircraft Operations Room at Furze Hill, Mistley, which controlled the Searson’s Farm battery and all of the anti-aircraft sites in the Harwich area, and is listed at Grade II (National Heritage List 1391976).

Source: Historic England


Books and journals
Cocroft, W D, Cold War Monuments: An Assessment by the Monuments Protection Programme, (2001)
Cocroft, W D, Thomas, R J C, Cold War - Building for Nuclear Confrontation 1946-1989, (2003)

Source: Historic England

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