Clocking, winding back an odometer so a car looks less used than it is, is often treated as a rare, old-fashioned crime. It is neither. Digital dashboards made it a cheaper job, not a harder one, and the incentive is simple: knocking tens of thousands of miles off a car can add thousands to its price.
To measure it, we analysed the odometer sequence of every vehicle in the DVSA's published MOT record from 2022 to 2024. A reading that falls between two tests, or leaps by more than the car's history can explain, is the fingerprint of a tampered odometer. Here is what the whole national record shows.
The scale of it
Across 34,838,049 vehicles with enough MOT history to check, 309,883 carry mileage that does not add up: one in every 112. Two patterns make up that total.
A decrease is unambiguous: an odometer cannot legitimately go down. An implausible jump can be a correction or a test-station typo, so it is the smaller and more cautious of the two counts.
The older the car, the worse it gets
Clocking is not spread evenly. It climbs steadily with a car's age, because older, higher-mileage cars are where winding the clock back changes the price most. A car over twenty years old is more than three times as likely to be flagged as one aged three to six.
Share of checkable vehicles flagged, by age, and how many times more likely than a car aged 3 to 6. The rate climbs from 1 in 164 to 1 in 51.
By make
The spread between makes is narrower than the spread by age, and it says more about how long and hard a brand's cars are kept than about the badge itself. Marques that sit at high mileage in later life, and change hands more, show up more often.
Flag rate among makes with at least 100,000 checkable vehicles. Motorcycle-only brands are excluded so this reads as a car comparison.
What clocking actually costs the buyer
The mileage on the dash can be corrected on paper, but the wear cannot. A clocked car arrives with tyres, timing belts, clutches and suspension that its apparent mileage says are barely run in, and its real mileage says are due. You pay a low-mileage price for a high-mileage car, then pay again when the parts that were quietly overdue start to fail.
It is also fraud when a clocked car is sold without disclosure, though owning the tool and altering your own odometer is not itself illegal, which is exactly why the practice persists.
How to protect yourself
Every MOT since 2005 records the odometer, and that history is public, so the single best check is free. Run any reg through our mileage check and the readings are charted in date order with the anomalies flagged for you; our guide to spotting a clocked car covers the physical giveaways a chart cannot show. The one gap no odometer check can close is a car clocked before its first MOT, which is why the wear-versus-miles inspection still matters.
Method
The figures come from the DVSA's published record of every MOT test in Great Britain, 2022 to 2024, released under the Open Government Licence. For each vehicle we ordered its odometer readings by test date and flagged two things: any reading lower than an earlier one, and any increase too large to be plausible for the time elapsed.
What the numbers do and do not include
A flag is a strong signal, not a conviction: a small number of implausible jumps will be test-station typos, which is why decreases and jumps are counted separately and the jump threshold is deliberately cautious. Vehicles without at least two usable readings are excluded, and any car clocked before its first MOT, at three years old, is invisible to this method and to every mileage database, ours included. The true figure is therefore a floor, not a ceiling.