How do I prove a car's mileage has been altered?
Start with the free MOT history, which records the mileage at every test back to 2005 and needs only the registration. A reading that goes down, or that jumps implausibly between tests, is the clearest evidence there is. Add the service book, old invoices and any previous advert. Selling a car on a mileage the seller knows to be false is a misleading action under the Digital Markets, Competition and Consumers Act 2024, enforced by trading standards, and reporting it is free.
Do this first, before anything else. Open the free MOT history and read the mileage at every test. It costs nothing, needs only the registration, and settles most cases in under a minute — either the numbers rise sensibly or they do not.
What counts as evidence
| Source | Weight | What it shows |
|---|---|---|
| MOT history | Strongest | Free, needs only the registration, and shows the mileage recorded at every test back to 2005. A figure that falls between tests is close to conclusive. Print or screenshot it the day you find it. |
| Service records and invoices | Strong | Garages write the odometer on the invoice. A service at 90,000 miles in a car now showing 70,000 is the same contradiction as a reversed MOT and often covers the years between tests. |
| The previous advert | Strong | Cars are often listed more than once. A cached or saved listing showing a higher figure at an earlier date is direct evidence of what the seller was claiming then. |
| Condition against the reading | Supporting | A worn driver’s seat bolster, shiny steering wheel, worn pedal rubbers and replaced tyres on a car claiming low mileage. Suggestive rather than proof, but it is what makes you look at the rest. |
| A vehicle history check | Supporting | Paid checks aggregate mileage readings from several sources and may catch entries the MOT record misses. Useful corroboration; the underlying evidence is still the readings themselves. |
What the law actually says
The point people get wrong is that turning an odometer back is not, by itself, the offence. Instrument clusters get replaced and readings legitimately reset. What the law bites on is the selling: presenting a car on a mileage the seller knows, or ought to know, is false is a misleading action under the Digital Markets, Competition and Consumers Act 2024, which replaced the 2008 regulations for practices from 6 April 2025.
That distinction is practical, not academic. It tells you what you need to show: not that the number changed, but that the seller presented a figure they should have known was wrong. A dealer who had the MOT history available — and every dealer does — is in a difficult position on “ought to know”.
Guidance on unfair commercial practices is published by the Competition and Markets Authority. Read 2026-09-21.
What to do, in order
- Preserve the evidence before you raise it. Screenshot the advert, save the MOT history, photograph the odometer and the service book. Adverts get edited once a seller knows.
- Put it to the seller in writing. Email, not a phone call. State the readings and the dates. A genuine explanation — a replaced cluster, a documented correction — will come with paperwork.
- Report it to trading standards via the Citizens Advice consumer service. This is the enforcement route and is separate from getting your own money back.
- Pursue your own remedy in parallel. What you are entitled to depends on whether you bought from a trader or privately, and how you paid.
Before you buy, not after
All of this is easier as a check than as a complaint. Judge the reading against the car’s age with the mileage checker — a figure far below typical is not itself suspicious, but it is worth confirming against the history rather than paying the premium low mileage commands. And what to ask a dealer covers the rest of the paperwork.
A note on what this page is
A general explanation of published processes and where they sit in law, not legal advice about your purchase. For advice on a specific car, contact the Citizens Advice consumer service or a solicitor.
Frequently asked
Is clocking a car illegal in the UK?
Adjusting an odometer is not in itself the offence most people assume — an odometer can legitimately be replaced or corrected. The wrong is selling a vehicle on a mileage the seller knows or ought to know is false, which is a misleading action under the Digital Markets, Competition and Consumers Act 2024. Enforcement sits with trading standards and the Competition and Markets Authority, and it can be a criminal matter.
What is the quickest way to check a mileage claim before buying?
Look up the MOT history with the registration before you travel to see the car. It is free, takes a minute and lists the mileage recorded at every test back to 2005. If the readings only ever rise and rise plausibly, that is most of the reassurance available.
What if the mileage looks wrong but the MOT history is clean?
Gaps between tests are where alterations hide, particularly in the first three years when no MOT is due at all. Fill them with service invoices and the previous keeper’s records. A car with no paperwork for a long stretch is not proof of anything, but it is a reason to price accordingly.
Who do I report a clocked car to?
Trading standards, through the Citizens Advice consumer service, which passes reports on. Report the seller rather than only seeking your own refund — the enforcement route and the compensation route are separate, and a trader clocking one car is rarely clocking only one.
Can I get my money back if I bought a clocked car?
Your rights depend on who sold it. From a trader, a car that is not as described gives you rights under consumer law, and paying any part by credit card may give a further route. From a private seller the position is narrower but misrepresentation still matters. Take advice on your specific purchase rather than relying on a general page.
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