Every MOT in Great Britain is recorded, and the full record is published as open data. We analysed all 33,060,042 car MOTs from 2024 to see what actually fails.
71.7% passed first time. Another 5.5% had a fault fixed while they were at the test centre and passed the same day. The remaining 22.8% failed. A surprising share of those failures are things an owner could have spotted and fixed for a few pounds.
What fails most often
This counts failure items per 100 MOTs. One test can fail on several items, so the figures add up to more than the failure rate.
Failure items per 100 car MOTs, 33,060,042 tests in 2024. Source: DVSA MOT test data.
Why lights come top
Lights cover every bulb on the car, including the number plate light and the side repeaters, plus headlight aim and electrical items such as the horn, battery and wiring. A single blown bulb is a fail, and because nobody looks at their own brake lights, they go unnoticed for months. It is the cheapest failure to avoid.
What fails changes with the car's age
A young car and an old car fail for different reasons. In the first few years it is mostly wear items the owner controls. Later, it is the parts that wear out with time and miles.
Top three failure areas for each age band, and the share passing first time. 2024 car MOTs.
For cars aged 3 to 5 years, tyres and visibility (wipers, screen, mirrors) lead the failures. Both are things you can check on your drive. By 15 to 20 years, lights and electrics and suspension dominate, and rust starts to appear. Lights alone show the gap: 41 failure items per 100 MOTs on cars aged 15 to 20, against 3 on cars aged 3 to 5.
The checks to do before your MOT
None of these need tools. Do them the day before, with a friend if you can, so someone can watch the lights.
Lights
Switch on every light and walk round the car: headlights on dipped and full beam, sidelights, indicators front, side and back, hazards, brake lights, the rear fog light, reversing lights and the number plate light. Replace any that are out. A bulb costs a few pounds; a retest can cost you a day.
Tyres
The legal minimum tread is 1.6mm across the central three-quarters of the tyre, all the way round. A 20p coin is a rough guide: if you can see the outer band of the coin when it sits in the groove, the tread may be below the legal limit, so get it checked. Look for cuts, bulges and cords showing on the sidewalls, which are fails whatever the tread depth.
Wipers, screen wash and the windscreen
Top up the screen wash: an empty washer bottle can fail the test. Check the wipers clear the screen without smearing. Chips matter too. Damage bigger than 10mm in the area directly in front of the driver, or bigger than 40mm anywhere the wipers sweep, is a fail.
Warning lights, horn, seatbelts and plates
Start the car and check no warning lights stay on, such as the engine, airbag or ABS lights. Sound the horn. Pull each seatbelt out fully and check it locks when you tug it sharply. Make sure the number plates are clean, readable and not cracked.
Buying a used car? Read its old MOTs
Every past MOT result and advisory for a car is public. Advisories on a used car you are looking at are a preview of your next bills: "brake discs worn", "corrosion to sub-frame", "tyre near legal limit". Run the reg through our free MOT history check before you view it, and see how that model fares at MOT as it ages on our reliability pages.
You can also set a free MOT reminder. Driving without a valid MOT can mean a fine of up to £1,000, according to GOV.UK.
Common questions
Can I drive my car if it fails its MOT?
Only if your current MOT certificate is still valid and the failure did not include a dangerous defect. A dangerous defect means the car must not be driven until it is fixed. If the old certificate has run out, you can only drive it to a pre-booked MOT or to have the failed items repaired.
How early can I get my MOT done?
Up to a month minus a day before the current certificate runs out, and you keep the same renewal date. Testing earlier than that moves your renewal date to a year from the new test.
How much does an MOT cost?
The government sets a maximum of £54.85 for a car. Many garages charge less, sometimes much less, hoping to win the repair work, so it pays to shop around.
What is the difference between a major defect and an advisory?
Major and dangerous defects are fails. Minor defects are recorded but the car still passes. Advisories are notes on things that are wearing and will need attention soon; they do not affect the result, but they are a useful to-do list and a good guide to what a used car will need next.