The number of cars on UK roads showing mileage discrepancies has risen to one in 16, a jump of 25% according to new figures from automotive data experts Cap HPI.
The figure has leapt from one in 20 cars in 2014.
The figures emerge as what is believed to be the biggest clocking case in British legal history saw convictions for operators of a Runcorn-based chauffeur services company.
The practice of clocking takes place when drivers look to deliberately defraud second-hand car buyers when the vehicle is sold on.
Barry Shorto, head of industry relations at Cap HPI, said: “There are numerous reasons why clocking is on the up. The continued development of technologies to alter digital odometers, increasingly easy access to this technology via the internet and similarly, the ease of access to mileage adjustment services online, some of whom will behave legitimately, others less so.
“The increase in mileage-related finance arrangements such as PCP and PCH may also be a contributing factor.”
Cap HPI estimates that used car buyers now have a one in 16 chance of purchasing a vehicle with a mileage discrepancy, with the practice costing motorists over £800 million every year.
Shorto added: “The message to clockers is clear – it’s only a matter of time before they are caught and brought to justice. HPI remains committed against clocking as well as raising awareness of the value of its National Mileage Register.”
The HPI Check includes a mileage check against the National Mileage Register as standard, now with over 200 million mileage readings. It also confirms whether a vehicle is currently recorded as stolen with the police, has outstanding finance or safety recalls against it or has been written-off, making it the best way for consumers to protect themselves from fraudsters looking to make a fast profit.
Shorto added: “It can be almost impossible to tell a clocked vehicle just by looking at it, which makes a vehicle history check an even more vital form of protection for buyers.
“A clocked vehicle could be hiding serious levels of wear and tear, especially if it has been previously used as a high mileage private hire vehicle for a couple of years, meaning the additional cost of unexpected repairs or even a potentially serious safety threat to driver, passengers and other road users.”
Register (NMR) checks and investigations have grown by over a third in the last five years.