How DVSA Found Nearly 3 Million Cars Passed an MOT They Should Have Failed

• DVSA retesting found testers wrongly passed 10.7 percent of MOTs in 2023-24, a rate that points to close to 2.9 million unroadworthy cars on UK roads.
• Tyres, brakes and suspension were the defect categories testers missed most often, together accounting for more than two-thirds of the disputed results.
• DVSA disciplined 14 garages and sent 67 warning letters after its own examiners disagreed with local test outcomes, but drivers have no way of finding out if their garage was one of them.

The MOT Certificate on Your Windscreen Might Be Wrong

More than one in ten cars that passed their MOT last year should have failed it. That is the finding of the Driver and Vehicle Standards Agency’s own compliance survey for 2023-24, obtained by What Car? through a Freedom of Information request. Across the 26.7 million cars over three years old that need an MOT every year, the error rate points to close to 2.9 million vehicles currently on UK roads carrying a defect a tester should have caught and did not.

How DVSA Checks Its Own Testers

Each year DVSA examiners pull a random sample of vehicles that have just been through an MOT and retest them at the same site, checking whether the original tester applied the rules correctly. For the 2023-24 survey they retested 1,487 cars and disagreed with the original result in 13.7 percent of cases. Of those, 11 percent of the disputed cars had been given a pass certificate they should not have received, and 3 percent had been failed on a fault that was not there.

The error rate has moved only slightly in recent years. In 2022-23, DVSA disagreed with 12.2 percent of pass results; in 2021-22, it was 10.1 percent. The share of cars wrongly failed has crept up at the same time, from 2.1 percent in 2021-22 to 3.0 percent in 2023-24, so more drivers are also paying for repairs or retests they never needed.

Tyres, Suspension and Brakes Are Where Testers Slip Up

When DVSA’s examiners disagreed with a result, the fault almost always sat in one of three places. Tyre condition was the most commonly missed defect, disputed on 731 of the cars checked. Brakes came next, disputed on 678 cars, followed by suspension on 629. Lights, reflectors and electrics accounted for another 392 disputed defects. Steering, seatbelts and wheels were rarely the issue; together they made up fewer than 90 of the disagreements.

More than half of the cars with a disputed result, 55 percent, had three or more defects the retesters flagged as wrongly assessed, not a single borderline call. That points to some testers missing a pattern of problems on the same car, rather than mis-judging one close decision.

What a Wrong Pass Could Cost You

Even a valid-looking MOT certificate offers no legal cover if those missed defects are later found. A driver can still be fined up to £2,500, handed three penalty points, and disqualified for a dangerous defect. Responsibility for a car’s roadworthiness sits with the keeper, not the garage that signed off the test. An MOT pass is not a defence if a police check or a DVSA roadside inspection turns up the same tyre, brake or suspension fault the original tester missed.

Only 14 Garages Faced Any Consequence

Nearly 14 percent of retested results were disputed, yet DVSA took formal action against just 14 garages and sent advisory warning letters to 67 others. In 123 cases, examiners judged the discrepancy too marginal to act on. DVSA does not publish which garages were disciplined, so a driver whose car was wrongly passed, or wrongly failed, has no way of finding out whether their own test centre was among them.

What to Check Before Your Next MOT

DVSA sorts every MOT defect into one of three bands: Dangerous, Major or Minor. A Dangerous or Major defect fails the car outright; a Minor defect is recorded as an advisory and the car still passes. The compliance survey looks specifically at cases where a tester’s Major or Dangerous call, or lack of one, did not match what DVSA’s own examiners found on the same car a short time later. That is a narrower test than simply asking whether a car “should” fail in a general sense, which is why DVSA treats even a 10.7 percent discrepancy rate as a quality problem worth tracking year on year rather than dismissing as noise.

You can pull your car’s full MOT history, including every advisory and failure on record, for free at gov.uk’s MOT history checker. It will not tell you whether a past test met DVSA’s own standards, but it shows what each tester flagged, which is worth comparing if you switch garages. If a result feels wrong, you can ask a different MOT centre for an informal check, or raise concerns about a specific test with DVSA’s enforcement team through gov.uk.

Given where testers go wrong most often, it is worth checking your own tyres, brakes and suspension between tests rather than waiting for an MOT to catch a fault. For tyres, check tread depth with a 20p coin across the central three-quarters of the tyre, and look for cracking on the sidewall on all four, not just the two that look obviously worn. For brakes, listen for grinding or a high-pitched squeal when you slow down, and feel for the car pulling to one side. For suspension, a car that bounces more than once or twice after you push down hard on a corner, or clunks over speed bumps, is worth a second opinion before it turns into a dangerous fail rather than a minor one at your next test.

What an Advisory on Your MOT Certificate Really Means

An advisory is not a fail and carries no obligation to repair before your next test; the car still passes and you are free to drive away. But DVSA’s own figures show that disputed results rarely came down to one missed item. More than half involved three or more defects the retesters flagged together, which is why an advisory for a tyre, brake or suspension component is worth treating as an early warning rather than filing away for next year. If your last certificate carries an advisory in any of those three categories, getting it looked at now costs far less than discovering it was closer to a Major defect the next time round.

None of this means every MOT test is suspect. DVSA’s sample size is small next to the roughly 30 million MOT tests carried out in Great Britain each year, and the survey exists precisely so the agency can catch the minority of testers falling short before a pattern becomes a habit at a particular garage. For most drivers the practical lesson is narrower: know which three systems get missed most, and do not treat a clean certificate as proof that tyres, brakes and suspension need no attention until next year’s reminder letter arrives.

The gap between the two most recent surveys also hints at where DVSA’s attention has shifted. The share of cars wrongly failed rose from 2.2 percent in 2022-23 to 3.0 percent in 2023-24, even as the share wrongly passed fell slightly over the same period. Read together, the two trends point to testers applying the rules more strictly rather than more loosely, which is a reasonable outcome for DVSA’s compliance programme. A small and rising number of drivers are still paying for repairs, or a retest, on a car that never needed either.

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Sources:

• What Car?: MOT testers pass 2.9 million unroadworthy cars