The MOT history is free, takes 30 seconds to check, and tells you more about the true condition of a used car than almost anything else available to you before viewing. Yet the majority of used car buyers never look at it. Here's what the MOT history shows, how to read it correctly, and what patterns in the data tell you about a car's maintenance history and reliability.
What Is the MOT History and How Do You Check It?
Every car in the UK must pass an annual MOT test (mandatory from age 3 for most cars). The DVSA records every test — pass, fail, and the details of each — and makes this data publicly available. The record goes back to 2005 for most vehicles.
To check: go to check-mot.service.gov.uk or use AllCarsUK's free MOT checker. Enter the registration number. You'll see a chronological list of every test, with the date, the mileage recorded at the time, and whether the car passed or failed. For failures, you'll see what caused the failure. For all tests, you'll see any advisory notes from the tester.
This takes 30 seconds. There is no reason to view any used car without doing this check first.
Reading the Mileage — The Single Most Important Check
The mileage column in the MOT history is the most valuable data point available on any used car. Look at it before anything else.
The mileage should increase consistently between tests. If the mileage at any point is lower than the preceding test — even by 100 miles — the odometer has been altered. Clocking is illegal under the Fraud Act 2006, and a single mileage decrease in the MOT record is definitive, unarguable evidence. End of conversation. Walk away.
Also check whether the total mileage progression makes internal sense. A car accumulating 8,000–10,000 miles per year consistently for five years, then suddenly showing only 500 miles added in the most recent year, is unusual and warrants a direct question — was the car laid up, and if so why? A car showing 44,000 miles at its MOT two years ago that now reads 46,000 has covered just 2,000 miles in two years — ask whether it's been regularly driven or sitting unused, because extended periods of storage create their own maintenance concerns. A car with 65,000 miles currently showing on the clock whose MOT history shows it consistently accumulated 18,000 miles per year for several years doesn't mathematically add up — add the annual increments yourself and check that the current odometer reading is what the progression would predict.
Understanding Failures
A failure isn't automatically a dealbreaker — it depends entirely on what failed and whether it was fixed. Look at what specifically caused the failure:
Minor failures — lights, wipers, washer jets, or a non-functioning horn — are cheap to fix and tell you nothing alarming about the car's fundamental condition. A tyre failure followed by a pass at the next test is normal maintenance. If the service history shows these items were corrected promptly, there's no ongoing concern.
Moderate failures are worth investigating before dismissing or accepting. A brake failure is worth looking into specifically — check whether the failure reason was low pad thickness (normal wear, normal replacement), a binding caliper (a more significant issue), or uneven brake force (potentially indicating hydraulic or caliper problems). Look for evidence in the service history that the specific issue was addressed, not just that the car passed a subsequent test. An emissions failure on a diesel is worth treating cautiously — it can indicate DPF issues that are expensive to resolve permanently, particularly if the car has been used mainly for short journeys. A steering or suspension failure depends entirely on what specifically failed; a worn track rod end bush is a minor repair, while a compromised damper or a failing steering joint is more significant.
Serious failures are a different category. Structural rust — corrosion to the chassis, subframe, or structural floor areas — is the most significant. The MOT tester will record specifically what structural area is affected. Structural rust doesn't disappear when the car subsequently passes; it's been patched or painted over to achieve a pass. A car with structural rust advisories or failures in its history needs an independent structural inspection before you even consider buying it. Severe brake imbalance or steering mechanism failures in the history also warrant careful investigation — they indicate the car was driven in a potentially unsafe state until the test forced the issue.
Understanding Advisories — The Hidden Story
Advisories are the most underrated and most informative part of the MOT history for a used car buyer. An advisory is a note from the tester about a condition they observed that wasn't severe enough to cause a failure — but that should be monitored or addressed.
A single advisory means very little. The pattern of advisories across multiple years is extremely revealing:
The most significant warning pattern is the same advisory repeating across consecutive years. If the tester has noted “slight play in front nearside suspension joint” at three consecutive annual tests, that joint has not been replaced — it's still there, three years older, with three years more play in it. The owner either chose not to address it or didn't read the advisory closely. Either way, the condition is present when you're viewing the car. Similarly, a rust advisory that escalates across years — “light surface corrosion on nearside sill” becoming “significant corrosion on nearside sill” becoming “corrosion to nearside sill — monitor” — tells a specific story of neglect that isn't difficult to interpret. Brake advisories that recur year after year without documented repair in the service history indicate a pattern of reactive rather than preventive maintenance that tells you how the car has been looked after.
Not every advisory is a cause for concern. Tyre wear noted at a test, followed by no tyre advisory at the next year's test, means the tyres were changed — entirely normal behaviour. Surface corrosion on a 12-year-old car in age-appropriate areas (undersides, lower chassis, minor panel edges) is essentially universal on UK cars of that age and isn't alarming by itself. A windscreen chip noted as an advisory is minor and cheap to resolve. The question to ask of any advisory is always: what happened next? If the next test shows no recurrence, it was addressed. If the same note appears again a year later, it wasn't.
Gaps in the MOT History
A gap of more than 13 months between MOT tests means the car either wasn't on the road legally (SORNed — a Statutory Off Road Notification) or was being driven illegally without a valid MOT. Both situations warrant a question.
Plausible explanations for gaps exist: the owner was working abroad, the car was in long-term storage, the owner was recovering from illness. An explanation that doesn't correspond with the car's apparent condition or service history pattern raises more questions.
A gap immediately before the car was listed for sale is particularly worth probing — why was the car off the road, and what was being done to it?
Reading the Full Picture Before You View
Run the MOT check before you contact the seller. It takes 30 seconds. If the check shows a mileage decrease at any point, you don't contact them at all. If the check shows serious structural failures in the history, you either don't proceed or you require an independent structural inspection as a precondition. If the check shows patterns of advisory neglect — the same brake advisory for four consecutive years, a rust advisory that escalated without remediation — you adjust your expectations and your offer accordingly, or you decide the car isn't worth the risk.
If the check raises questions that have plausible explanations, ask the seller before you travel to view. “The MOT history shows a brake failure two years ago — can you tell me what was done to fix it?” is a perfectly reasonable question. A seller who can answer clearly and reference the specific service record entry confirming the repair is exactly the kind of seller you want to deal with — transparent, knowledgeable about their own car, and confident the history supports their asking price. A seller who gets defensive, can't explain the specific failure, or claims not to know about it is telling you something equally useful before you've invested a journey in the car.
Cross-reference the MOT history against the service history if the seller provides one. The MOT mileages should align with the service book entries for the same periods — if the service book claims an oil change at 52,000 miles but the MOT history shows no test until the mileage had already reached 58,000 miles, those records don't align. Either the service history is inaccurate about the mileage or the timing, or something else is inconsistent. Neither is automatically a dealbreaker, but both warrant a specific question.
Finally, check the most recent MOT date against today's date. If the MOT expires within the next two months, there's a real probability the next test will reveal items that are currently marginal advisories becoming outright failures. A car with four months left on its MOT versus a car with eleven months left is a meaningfully different proposition — the one with less time has more near-term uncertainty around what the next test will reveal. Some buyers use an imminent MOT as a negotiating point; others take a fresh MOT on an older car as an insurance policy worth paying for before listing. Either way, it's a data point worth noting before the viewing.
Check the MOT history before you go →
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Also see: How to Check a Car's History | How to Spot a Clocked Car | What to Check When Viewing | Avoid Used Car Scams