Decoy sites: one of the biggest secrets of the World War II

Find out more about the historic military/ordnance features dataset which is included in all Groundsure residential and commercial searches.

During the Second World War a secret department was formed at Britain’s Air Ministry to co-ordinate a strategy to defeat German bombing by deception. With the help of leading technicians from the film industry, a broad range of day and night decoy sites to mislead enemy bombers were built throughout the island (1).

This campaign of illusion was masterminded by an engineer and retired Air Ministry officer, Colonel John Fisher Turner, and did more to protect Britain’s forces and civilians from the Nazi threat than, at the time, they were allowed to know. (1) Colonel Turner formed a team with the best film studio tradesmen, carpenters, and engineers – all for the construction of an elaborate network of dummy airfields and hundreds of decoy sites (2).

Owing to the British weather, most pre-war films were made under cover with the film sets being mock-ups and clever lighting made them look like the real points of attack. This knowledge became an unexpected tool wisely used during wartime in an ingenious attempt to fool the German Luftwaffe.

These sites were set up in large areas of open space to protect the real sites they were imitating which could be towns, military bases, factories, airfields or railway marshalling yards and docks whose creation was only in an ingenuous attempt to trick the Luftwaffe. (1)

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. Urban decoy fires were known as `SF’, `Special Fires’ and Starfish, to distinguish them from the smaller QF installations. These were 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. Only these sites were considered to have saved 2,400 lives and 730 air raids.(3)

Tanks containing paraffin or diesel were placed on top of 20ft towers, arranged to resemble rows of buildings or industrial complexes. A valve that operated like a toilet flush was opened to release the fuel on to burning coal, creating an instant blaze and engulfing the area in black smoke. Then the fire was flushed with water to send a column of steam into the night sky. Result: a rather convincing mock-up of a bombing raid that hit its target.(3)

It is believe that there were around 230 dummy airfields in the UK and 400 dummy urban and industrial sites although very little now survives of any of these decoys, most having been cleared after the war.(4)

Due to the heavy bombing several areas across the country were exposed to, the risk of encountering UXO becomes an important factor to take into account in construction projects and new developments. Experts have revealed that more than 14,000 unexploded devices were discovered on construction sites only between 2006 and 2009 which lead to unexpected delays with project timescale and additional costs to manage the situation.

In recognition of this, Groundsure offers its Groundsure UXO, an essential search that provides our clients with an unrivalled view of geo-referenced unexploded ordnance throughout the UK. Groundsure UXO provides a preliminary risk assessment based on hundreds of datasets, the analysis from thousands of projects to mitigate bomb risk since 1991, previous bomb excavations and accurate bomb density mapping. The search allows UXO hazards to be excluded from further consideration or provide recommendations for further action where appropriate.

Groundsure has a historic military/ordnance features dataset which is included in all our residential and commercial searches. This is a unique database that has been produced following research of military records with features judged to be of contaminative concern and digitised using available mapping and historical records. Many of these features were not present in standard Ordnance Survey mapping for security reasons.

Further information on the Groundsure UXO report can be found here:


(1) The military history of Slindon. Slindon Estate at war. Available at:

(2) BBC News, 2013. How the British film industry helped win World War II. Available at: [Accessed 7th March 2014]

(3) Mail Online, March 2013, Operation Starfish: Extraordinary story of Second World War sites designed to look like burning cities which saved 2,400 lives and diverted 730 air raids. Available at: [Accessed 7th March 2014]

(4) Historic England. World War II bombing decoy, 400m north west of John Cross. Available at: [Accessed 7th March 2014]

This article was submitted to be published by Groundsure as part of their advertising agreement with Today’s Conveyancer. The views expressed in this article are those of the submitter and not those of Today’s Conveyancer.

Today's Conveyancer