Buying a used car without checking its history is like buying a house without a survey. You might be fine — or you might be buying someone else's financial or legal problem. The checks cost very little and take minutes. There is no good reason to skip them, and very good reasons to do every one before you view, not after.
This guide covers the complete set of checks, what each one reveals, what to do if the results show problems, and the order in which to run them.
Start With the Free Checks
MOT History — Free at AllCarsUK or GOV.UK
The MOT history is the single most informative free check available on any used car. Enter the registration number on AllCarsUK's free MOT checker or at check-mot.service.gov.uk to see every MOT test going back years — including passes, failures, and critically, the advisories.
Advisories are items that were noted at the test but weren't serious enough to fail the car. A single advisory is unremarkable. The same advisory appearing in three consecutive tests means the owner has been aware of the issue for three years and hasn't addressed it. That tells you something specific about how the car has been maintained.
The mileage recorded at each test is the most important data point in the MOT history. It should increase consistently between every test, year on year. If the recorded mileage decreases between any two consecutive tests — even by a small amount — the odometer has been tampered with. There is no legitimate explanation for a vehicle's recorded mileage to go backwards, and any seller who offers one is lying to you. Walk away.
Unusual mileage jumps in a single year are worth questioning even when the direction is correct. A car that accumulates 8,000–10,000 miles per year for several years and then shows 30,000 miles in one year isn't automatically fraudulent — the owner may have changed jobs or moved — but it deserves a direct question and verification against the service history for that specific period. A convincing explanation supported by paperwork is fine. A vague response isn't.
Recurring advisories are the most commonly underestimated part of the MOT history. A single advisory for a slightly worn tyre or a minor corrosion note is unremarkable on any used car. The same advisory appearing at three or four consecutive annual tests means the owner knew about the problem for years and repeatedly chose not to address it. That's direct evidence of how the car has been maintained — or not — and you should factor it into your offer.
Long gaps between MOT tests need an explanation. If a car went two or three years without a certificate in the history, it was either formally SORNed and taken off the road, driven illegally, or there's something the seller isn't telling you about that period. Ask specifically: why was the car off the road, was it being repaired, and what work was done? If the car was in storage or off the road for a legitimate reason, the seller should be able to explain it without hesitation.
Multiple consecutive failures across different annual MOT tests — where the car had to return for retests because it failed the initial inspection several years running — suggest a pattern of minimal, reactive maintenance rather than proactive upkeep. It's not an automatic reason to walk away, but it tells you the car has been fixed when it broke rather than maintained to prevent breakdowns. That's a different kind of car to own, and it should be reflected in the price and your pre-purchase inspection.
DVLA Vehicle Check — Free
At vehicleenquiry.service.gov.uk you can check whether a car is currently taxed, when the MOT expires, and verify basic vehicle details (make, colour, engine size). This takes 30 seconds and confirms the basics match what the seller is telling you. If the colour, engine size, or vehicle type on the DVLA record doesn't match the car in front of you, walk away.
The Paid Check — Worth Every Penny
Vehicle History Check (HPI, Experian, AA, RAC)
Several companies offer comprehensive vehicle history checks for £10–£30. HPI Check is the most well-known; Experian Car Check, the AA Car History Check, and the RAC History Check are comparable alternatives. All draw from broadly the same databases. Any reputable check service includes:
Outstanding finance — this is the most important check. If the previous owner borrowed money against the car using a hire purchase or conditional sale agreement, the lender retains a security interest in the vehicle. That interest follows the car, not the owner. If the seller hasn't repaid the finance before completing the sale, the lender can legally repossess the car from you — even though you paid for it in good faith and have done nothing wrong. This is not a hypothetical scenario. It happens to used car buyers in the UK every year. The check that prevents it costs £15.
Write-off status — if the car has been declared a total loss by an insurer, this is recorded and graded by category. Category A and Category B are total write-offs: the car should have been crushed and must never return to public roads. If a history check shows a Category A or B marker on a car that's being offered for sale, contact Action Fraud and walk away immediately.
Category S (formerly Category C before 2017) means the car suffered structural damage and was assessed as uneconomic to repair relative to its value. It can legally return to the road after professional structural repair and DVLA re-registration. A correctly repaired Cat S car is roadworthy and can represent good value at a price that reflects the history — but the word “correctly” is doing a lot of work there. Always get a Cat S car independently inspected by a qualified mechanic or structural inspection specialist before proceeding, and never take a seller's word that the repair was done to a professional standard without evidence.
Category N (formerly Category D) means non-structural damage — cosmetic, mechanical, or electrical — was assessed as uneconomic to repair. There are no structural repair requirements for a Cat N car to return to the road. A well-repaired Cat N write-off at an appropriate discount is generally a more straightforward buy than a Cat S. The check is still worth doing to understand what the original damage was and whether the visible repair work appears consistent with the claimed incident.
Stolen status — if the car is recorded as stolen, purchasing it is a criminal matter. The police will take the car and you will not be compensated.
Number of previous owners — provides context. Unusual ownership patterns (many owners in short periods, or owners who kept it for only months) can indicate problems that prompted rapid sales.
Mileage discrepancy alerts — cross-referenced against multiple databases including manufacturer systems, fleet records, and the MOT history. Flags any inconsistency.
The cost is £10–£30. On a £5,000 car, this is 0.2–0.6% of the purchase price. On a £15,000 car, it's 0.1%. The check has potentially unlimited downside protection — there is simply no justification for skipping it.
What to Do If the Check Shows Problems
Outstanding finance means you walk away unless the seller can provide documented confirmation — in writing, from the finance company directly — that the agreement has been fully settled and the vehicle is unencumbered before the sale completes. "I'll pay it off with the money you give me" is not an acceptable position. The finance company's security interest follows the car, not the debt. If the seller uses your payment to repay the loan, the timing matters — if the car changes hands before the finance clears, the lender retains a valid claim on the vehicle. Get written confirmation of settlement before handing over a penny. If the seller can't or won't provide this, assume the finance is still live and decline.
A Category S write-off flag means book an independent inspection before you go any further. A structural specialist or a qualified mechanic who knows what they're looking for can assess whether the repair was done to a professional standard. If it was, and the car is priced to reflect the write-off marker, it can be a reasonable buy. If the repair is substandard — uneven seam welds, misaligned pillars, filler over structural damage — walk away regardless of price.
A stolen flag means contact Action Fraud via their online reporting tool (actionfraud.police.uk) and, if the seller is present, the police directly. Do not complete the purchase under any circumstances. Do not hand money over. Do not attempt to "sort it out" with the seller — the car is not theirs to sell, and proceeding knowingly is a criminal matter for you as well as them.
A mileage discrepancy — a decrease in the recorded mileage at any point in the history — is fraud under the Fraud Act 2006. Challenge the seller directly with the specific data: "The 2021 MOT shows 74,000 miles. The 2022 MOT shows 61,000 miles. How do you explain that?" If they can't, leave. There is no legitimate explanation, and any story they tell is an attempt to keep you engaged long enough to complete the sale.
Check the MOT history before you go →
Free MOT checker at AllCarsUKRegistration plate only. Every test, advisory, and mileage. Free, no account needed.
The Order to Run the Checks
Run the free checks — MOT history and DVLA vehicle details — before you do anything else. These two checks together take under two minutes and will occasionally reveal something that makes the entire process pointless before you've invested any time. A mileage discrepancy in the MOT history or a basic detail mismatch on the DVLA record ends the conversation before it starts.
If the free checks are clear and you're seriously interested, run the paid history check before you travel to view. At £10–£30 this is not a meaningful cost relative to what you're about to spend. Outstanding finance and write-off status are the two check results that can make a car unsaleable or legally problematic, and both are invisible to the naked eye at a viewing. Discovering either of these issues after you've driven 150 miles to look at the car is a worse experience than discovering it from your desk.
During the viewing itself, physically cross-reference the VIN printed on the V5C logbook against the VIN plate visible at the base of the windscreen on the driver's side, and the stamped number in the doorjamb or engine bay. These should be identical. A discrepancy between the logbook VIN and the car's physical VIN means either the logbook has been fraudulently altered or the car has been “VIN plated” — a scam where legitimate documents are applied to a stolen vehicle. Either scenario is a reason to contact the police rather than complete a purchase.
Also see: How to Spot a Clocked Car | Outstanding Finance Guide | Avoid Used Car Scams | What to Check When Viewing