About 27% of cars and light vans fail at the first attempt. Almost none of it is exotic. The same handful of parts account for most of it, and several of them cost less than the retest.
DVSA groups defects into sections, and the ranking barely moves year to year. Lighting and electrics is always first. Suspension is always near the top by share of failures. Tyres, brakes and driver visibility fill out the rest.
| Area | Share of failures | Typical cause |
|---|---|---|
| Lamps, reflectors, electrical | Around 11% | Blown bulb, cracked lens, misaligned headlamp |
| Suspension | Close to 20% of initial fails | Worn bushes, leaking shock absorber, corroded spring |
| Brakes | High, often flagged dangerous | Handbrake efficiency, worn pads, imbalance |
| Tyres | High | Below 1.6mm tread, sidewall damage, wrong sizes |
| Driver visibility | Moderate | Wipers, washers, chip in the swept area |
This is the frustrating part. A large slice of MOT failures are things you could have found in your driveway in ten minutes.
Bulbs. Every bulb has to work, including the number plate lights and the rear fog. A single dead bulb is a major defect and a fail.
Washers and wipers. Empty washer bottle, torn wiper blade, or a smear across the swept area of the screen. All fails. The washer bottle is free to fix.
Number plate. Wrong font, wrong spacing, a green flash where it should not be, or a plate so faded the tester cannot read it.
Registered keeper details on the screen. Not a fail, but a chip larger than 10mm in the driver's line of sight is, and larger than 40mm anywhere else in the swept area is too.
Boot and bonnet catches, seatbelts, horn, mirrors. All checked. All cheap.
Suspension. The single biggest cost risk. A leaking shock absorber, a snapped coil spring or perished bushes are common on any car over about eight years old, and they are labour heavy.
Corrosion. If a structural area within 30cm of a mounting point for the suspension, steering, seatbelts or brakes is corroded, it fails. On an older car this can be the end of it economically.
Emissions. A diesel that smokes visibly fails outright. A failed catalytic converter or diesel particulate filter is a four figure job on some cars.
Brakes. Pads and discs are routine. A seized caliper or a corroded brake line is not.
| Job | Typical UK cost |
|---|---|
| Bulb replacement | £5 to £25 fitted |
| Wiper blades, pair | £15 to £45 |
| Front brake pads | £90 to £180 |
| Front pads and discs | £180 to £350 |
| One shock absorber | £120 to £300 |
| Coil spring | £120 to £250 |
| Budget tyre, fitted, 15 to 16 inch | £45 to £80 |
| Windscreen replacement | £180 to £450, often free on a chip repair with comprehensive cover |
If your vehicle fails, you get a partial retest free if you leave it at the test centre and it is repaired and retested before the end of the next working day. If you take it away and bring it back within 10 working days, you get a partial retest, and many garages do that free or at a reduced fee, though they are allowed to charge.
Beyond 10 working days it is a full test at the full fee. So if you fail on a Friday, that clock matters.
You also do not have to use the garage that failed it. If the quote feels high, take the failure sheet elsewhere. The defect list is standardised.
None of that guarantees a pass. It removes the cheap, avoidable fails, which is most of them.
Can I drive my car to the MOT if the current one has expired? Yes, but only to a pre booked test appointment, or to or from a garage for repairs. Anywhere else and you risk the fine.
Does a service count as an MOT? No. They are separate. A service is the garage's own checklist. The MOT is a legal roadworthiness test with a standardised defect list.
Will the garage fail it on purpose to sell me work? The vast majority will not, and DVSA audits testers. If you are unsure, take the failure sheet to a second garage for a quote. You are never obliged to have the repairs done where you tested.
Does an advisory mean I have to fix something? No. An advisory is a note that something will need attention later. It does not affect the pass.
Mileage fraud is legal to commit and illegal to profit from. The MOT history is the cheapest way to catch it. Here is exactly what to look for.
The three year rule, the one month early rule, the £1,000 fine, and the handful of exemptions that actually apply. Sourced from GOV.UK.
The four MOT result categories, which ones fail you, which one means you must not drive the car at all, and how to read a defect list.
Official DVSA MOT testing figures for Great Britain, laid out plainly. Test volumes, initial failure rates by class and by vehicle age, and the defect categories behind the failures.
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