More than 16% of vehicles that have had at least three owners have a discrepancy between the mileage given by the used car dealer and the actual mileage, according to investigations by HPI Equifax National Mileage Register.

Andrew Wenzel, HPI Equifax automotive managing director, said: “Of the sample of 300,000 vehicles investigated by the HPI Equifax National Mileage Register, 1 in 15 had a discrepancy. The older the vehicle and the more keepers it has had, the higher the risk of clocking.”

Less than 3% of cars with one owner had a discrepancy, but more than a quarter of cars with five owners had been clocked.

He highlighted the HPI Equifax NMR Double Indemnity scheme, which protects dealers against losses due to a lack of due diligence, provided the dealer acted legally.

“Should a court successfully prosecute an NMR member, due to any failure of the NMR, Equifax will provide compensation equal to twice the amount of any fine imposed,” he said.