One in seven used cars shows signs of tampering
Used-car buyers are being urged to take extra care after new data shows tampering is rife. Around one in seven cars on UK roads has either had its mileage turned back or its identity hidden - tricks that can make you overpay and end up with an unsafe or worthless vehicle.
The scale of the problem
A study of more than 550,000 UK cars checked between January and September found 16.3% had signs of odometer tampering or VIN (vehicle identification number) discrepancies.
Carly, a diagnostics platform that ran 2.5 million vehicle checks during that period, says the issue affects all regions - not just big cities.
The financial hit for drivers
Experts estimate motorists are losing around £750 million a year to mileage fraud. The average victim pays roughly £4,750 more than the car is actually worth.
Beyond overpaying, buyers face unexpected repair bills, higher safety risks, or even the possibility of having a car seized if its true history comes to light.
Why VIN tampering is even worse
Altering a VIN can hide whether a car was stolen, written off, or rebuilt after a crash. That means a seemingly normal car could actually be unsafe - and police can seize it at any time with no compensation for the buyer.
How fraudsters are getting smarter
Clocking used to mean manually rolling back a dial. Now, “mileage blockers” - small plug-in devices that pause the odometer - are being sold online for £200 to £250.
They’re advertised as “undetectable” and can stop mileage recording across multiple systems, making fake histories look genuine.
Millions of buyers at risk
With 7.6 million used cars sold last year, and even more in 2025 so far, millions of drivers could be affected. Based on those figures, over 1.2 million second-hand cars may have been manipulated before being sold.
How to protect yourself
Carly recommends running a digital check before you buy. Their £41 Used Car Check plugs into a vehicle’s OBD port and compares mileage across its internal systems, flagging any resets or mismatches that wouldn’t show up in a simple MOT history.
The legal loophole
Surprisingly, it’s not illegal to alter a car’s mileage in the UK - only to sell it without declaring that it’s been changed.
Proving intent to defraud is difficult, which makes prosecution rare. Experts argue that current laws let scammers exploit this grey area while reputable dealers and buyers pay the price.
Stay smart when buying used
As used-car demand soars and new-car prices remain high, proper digital checks are essential.
Always verify a car’s history before handing over money, especially when buying privately or from smaller dealerships. A few minutes of checking could save you thousands - and a lot of trouble later.
