Decoy Control Building

Summary

In the fields to the north of Chew Magna was a ‘QL’ and ‘Starfish’ bombing decoy site, which was part of a defensive network designed to protect Bristol from aerial bombardment during the Second World War. The surviving control building would have been the base from which electrical and pyrotechnic effects were orchestrated, first simulating urban blackout lighting, and then igniting controlled fires to mimic the effects of successful bombardment.

Reasons for Designation

The Decoy Control Building is scheduled for the following principal reasons:

* Period: decoy sites were an important component of the nation’s defence policy adopted to minimise damage from aerial bombardment during the Second World War, and are therefore highly representative of this period. The site at Chew Magna was part of the network of Starfish and QL civil decoys constructed to protect Bristol – a key industrial, commercial and transport hub – and contributes to our understanding of the scale, ingenuity and technical sophistication employed in Britain’s civil defence and deception systems.
* Rarity: while over 200 ‘Starfish’ decoys were created, the great number were cleared after the war, and few control buildings are known to survive.
* Group value: one of a series of decoy sites protecting Bristol, which together illustrate the strategic intent and integrated nature of urban decoy defences.
* Survival: as a well-preserved upstanding structure, retaining the general, part-subterranean form, internal layout and key characteristics, and is a good representation of its type.

History

The Second World World saw the emergence of aerial bombardment as a decisive instrument of warfare, and to counter this threat, the United Kingdom maintained a flexible and diverse mechanism of air defence throughout the war. This included the early warning of approaching aircraft, through radar and visual detection, and the local defence of towns, cities and other vulnerable points using anti-aircraft gunnery and balloon barrages. But less conspicuously, many potential targets were shadowed by decoys – dummy structures, lighting displays and fires – designed to draw enemy bombs from the intended points of attack. Britain's decoy programme began in January 1940 and developed into a complex deception strategy, using four main methods: dummy aerodromes; diversionary fires; simulated urban lighting; and dummy factories and buildings. In all, some 839 decoys are recorded for England in official records, built on 602 sites (some sites containing decoys of more than one type). This makes up the greater proportion of the around 1000 decoys recorded for the United Kingdom. The programme represented a large investment of time and resources. Apart from construction costs, several thousand men were employed in operating decoys, the fortunes of which were closely tied to the wartime targets they served. The decoys were often successful, drawing many attacks otherwise destined for towns, cities and aerodromes, saving many lives.

Chew Magna was one of a series of eight bombing decoy sites to the south of Bristol, and one of six which were SF, or Special Fire sites, which became known as Starfish. It was built in late 1940 and operated by lighting a series of controlled fires during an air raid to replicate the effects an enemy aircrew would expect to see when their target had been successfully hit. The decoys included variation in fire type, duration of burning and speed of ignition. Fires were set in discrete areas defined by firebreak trenches and controlled from a remote shelter. Chew Magna was also the site of a 'QL' civil decoy, mimicking the small lights of an urban blackout. The two decoy sites shared a control building, which would have housed an operations room and provided the decoy crew with shelter. There is also evidence that the site had four Z rocket batteries; their bases survive, pushed onto the riverbank, to the west. The site is referenced as being operational until 1943 and is known to have attracted bombs.

Details

PRINCIPAL ELEMENTS: the monument includes the standing and buried remains of a Second World War bombing decoy control building, dating to 1940. It is located on agricultural land to the north of the village of Chew Magna, some 4 miles south of Bristol, where it formed part of a series of decoy sites designed to draw aerial bombardment away from the city.

DESCRIPTION: the control building is located on sloping ground, overlooking a lower, level area to the south-west.

A red brick structure with a reinforced concrete roof. It has a rectangular footprint.

The building is partially subterranean, with earthen banks, somewhat eroded, providing additional protection from bombardment. On the west elevation, two parallel concrete-capped, sloping brick walls project, forming the entrance to a central passage, and a short detached blast wall stands in front. A low brick plinth runs along the west elevation, partially covered in earth, and there is a ceramic pipe from the southern control room. A second pipe, likely the exhaust for a generator, is at a higher level on the south elevation; the round opening has a truncated ceramic pipe within a socket. On the roof of the northern half of the structure is a square brick escape hatch; iron fixings for the ladder survive.

Internally, the shelter follows the standard pattern for a decoy control building, with a central passage with a generator room on the right and control room on the left. Both rooms have the remains of paintwork on the walls with outlines of signs and boards. There are timbers around the doorways and elsewhere with the remains of light switches and wiring. The control room, to the north, has an escape hatch, and there are two openings within the brickwork for cabling. The generator room, to the south, and has two ceramic pipe in/outlets.

EXTENT OF SCHEDULING: the scheduling comprises a single area containing the control building, and includes a 2.5m buffer for its support and preservation.

Sources

Books and journals
Dobinson, C S, Twentieth Century Fortifications in England: Volume 3. Bombing Decoys of WWII, (1996)
Dobinson, C S, Fields of Deception: Britains Bombing Decoys of WWII, (2000), 93, 109, 147

Websites
67328: Second World War bombing decoy (C1b), Chew Hill, Chew Magna, Bath & NE Somerset Historic Environment Record, accessed 11/07/2025 from https://www.somersetheritage.org.uk/record/67328
Penny, J, 'The Air Defence of the Bristol Area 1937-44', The Bristol Branch of the Historical Association Local History Pamphlets, accessed 06/01/2026 from https://bristolha.org/wp-content/uploads/2019/09/bha090.pdf

End of official list entry

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