Wiltshire Police are appealing for witnesses or dash cam footage following a spate of incidents involving heavy goods vehicles having fuel syphoned on the A303.
In a statement, they said, "The incidents are believed to have occurred between July 4 and 6, most likely between the hours of 11 am and 6 am on either night.
"A number of HGV vehicles which had been parked up in laybys on the A303 between Warminster and Amesbury had fuel syphoned and stolen whilst the drivers were asleep inside their vehicles.
"To date, we have had reports of five vehicles being targeted, but we believe there may be further incidents which have not yet been reported.
"In one incident, approximately 270 litres of fuel was stolen from the tank of a tractor parked in a lay-by approximately three miles from Solstice Park.
"Anyone with information should call 101 and quote log number 54230070523.
"Alternatively, call CrimeStoppers anonymously on 0800 555 111."

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