World War II bombing decoy WRI Spinnels Farm


Heritage Category:
Scheduled Monument
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Date first listed:


Ordnance survey map of World War II bombing decoy WRI Spinnels Farm
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The building or site itself may lie within the boundary of more than one authority.

Tendring (District Authority)
National Grid Reference:
TM 15924 30219

Reasons for Designation

World War II 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: day and night dummy aerodromes (`K' and `Q' sites); diversionary fires (`QF' sites and `Starfish'); simulated urban lighting (`QL' sites); 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 c.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. They saved many lives. Urban decoy fires were known as `SF', `Special Fires' and `Starfish', to distinguish them from the smaller `QF' installations. Each town was protected by a cluster of these decoys, the most technically sophisticated of all the types, with each Starfish replicating the fire effects an enemy aircrew would expect to see when their target had been successfully set alight. The decoys included variation in fire type, duration of burning and speed of ignition. In a permanent Starfish all fire types were used, set in discrete areas defined by firebreak trenches and controlled from a remote shelter. The whole array was linked by a network of metalled access roads. `Temporary Starfish' (all built in 1942 to counter the threat from the so-called Baedeker raids against historic towns and cities) only had basket fires. In all, 228 decoys with a Starfish component are recorded in England, 37 of which were `Temporary Starfish', and the rest `Permanent'. The Permanent sites were located mostly in central England, close to the urban and industrial targets they were intended to protect; temporary sites, like the Baedeker targets they were protecting, were confined to southern and eastern England. QF sites were first provided for the night protection of RAF airfields, but from August 1941 their role was extended to protect urban centres. Although similar to Starfish, they differed in being considerably smaller, using a limited range of fire types and being sited for the local protection of specific vulnerable points rather than whole cities or conurbations. These new QF sites of 1941-2 fell into four groups, for the protection of: urban and industrial targets (the `Civil Series', located mostly in the west Midlands, north-west and in the Middlesbrough area); Royal Navy sites (these were few in number and sited to protect coastal bases); Army sites, to protect ordnance factories or military installations (these existed in a sparse belt running from central southern England into the west Midlands); and oil installations and tank farms (the `Oil QF' sites). In all, only about 100 QF sites were operational in England. Very little now survives of any of these decoys, most having been cleared after the war. All sites with significant surviving remains will be considered of national importance, as will those where a well-preserved night shelter has been identified.

The survival of major components of the World War II bombing decoy documented in wartime records as `WRI Spinnels Farm' is of particular interest to the study of bombing decoy design. The decoy is a World War II N series (naval) decoy, one of an original deployment of five in Essex of which WRI Spinnels Farm is one of only two which survive in good condition. The other decoy at Kirby-le-Soken, the subject of a separate scheduling, can be seen as a partner to this one in the defence of Harwich's naval installations, Spinnels Farm having been designed to replicate a successful bombing raid on the Sea Mine Depot at Wrabness, and Kirby-le-Soken to replicate a successful raid on Harwich dockyard.


The monument includes the night shelter of a World War Two bombing decoy, situated south of the Stour river valley, some 450m south west of Spinnel's Farm. It occupies an elevated position on a ridge of high ground overlooking the decoy area to the south.

Documented in contemporary records as `WRI Spinnels Farm', the site was a World War II N series (Naval) decoy controlled from Harwich. This class of decoy was designed specifically for the protection of naval installations - in this case the Sea Mine Depot at Wrabness sited two miles to the north. The site is a QF type replicating the night-time fires one would expect from a night-time bombing raid on a specific target mostly by using basket fires.

The decoy site was an elaborate affair and would have utilised numerous fires ignited electrically from an earth-covered bunker or night shelter. The night shelter which housed the electrical ignition equipment for the fires overlooks the decoy area to south east. It is a brick and concrete bunker with a maximum external length of 12m and is covered with earth to protect it from stray bombs. It is divided into two main rooms, the Operations Room (4m by 3.2m internally), the Operations Room (3.2m by 3.8m internally), and also has a small toilet room in between the two. The Operations Room has an escape hatch with a steel ladder; remains of the flue outlet for the stove and four ceramic pipe outlets, thought to have been for chanelling the electrical switchgear cabling to the outside, survive. In the Engine Room the engine bed remains, with three steel exhaust outlet pipes leading through the north wall to the outside.

War Office documents relating to the equipment and manning of the Bombing Decoy WRI Spinnels Farm show that it was operational in August 1941 (the earliest reference to it is dated 1st August), and was certainly in use in March 1942 (latest written reference); although no further specific documentary references can be found, it may have continued in use through to the end of the war.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

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Books and journals
Dobinson, C S, Twentieth Century Fortifications in England: Volume 3. Bombing Decoys of WWII, (1996), 116-8
Black and white vertical, RAF, 106G-UK 1673-3161, (1946)
Colour prints in ESMR, Nash, F, (1999)
Tyler, S, MPP Film , (2000)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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