What is an MOT?

All you need to know about the inspection that ensures used cars are safe and legal: your guide to the MOT

BuyaCar team
Jun 9, 2021

The MOT test is the official safety check that all cars must have - it should be carried out at an MOT testing station, which may be part of a garage, or an independent business that's dedicated solely to doing tests. A car's first test should take place on its third anniversary, and then each year thereafter.

If a car passes the test, it is awarded a pass certificate that is valid for 12 months. The test is a snapshot of the car's condition on one particular day; it cannot be assumed that the car will be just as safe the day after the test, or six months after.

That's because parts can break over the course of a year, and wear and tear means that parts that were fine six months ago are no longer safe. An example of this is the tread on a car's tyres. While they may have had enough tread to pass an MOT test, if you cover thousands of miles in the following months, this could be enough to take them below the legal limit, offering very poor grip, especially in the wet. As a result, even with a valid MOT, you will still need to keep tabs on the condition of the car throughout the year.

The MOT test isn’t concerned with non-safety related areas or components. So a used car with an MOT certificate isn't guaranteed to be mechanically sound and any number of other systems - like the air-conditioning - may not be working, even with a full MOT. However, the test confirms the car was roadworthy when assessed and highlights both serious and minor safety issues at that time.

Testing takes around 40 minutes and the maximum it will cost you is £54.85, although you can get it for much less if you shop around. It’s often bundled in with servicing at a lower price. Some of the best value MOT test centres are often ones run by councils. These are not often advertised but are open to the public.

When purchasing a used car over three years old you can also check the MOT history online to see what was flagged on the previous MOTs and whether it has passed or failed each test. This report - accessed by simply entering the car's number plate - shows whether the car passed its previous MOTs and whether there were any advisories - elements that need to be monitored to ensure they don't become unsafe. Advisories have been categorised as dangerous, major and minor since 2018.

Looking at the MOT history can give you a feel for how reliable the car has been to date and whether it has been looked after. A car that has had advisories for the same elements year after year probably hasn't been meticulously cared for. Meanwhile, another model which has passed every year with no advisories mentioned is more likely to have been well maintained - either being regularly serviced or having any issues quickly fixed. But remember, this is just a guide.

When does a car need an MOT?

  • A car first needs to undergo an MOT when it reaches the third anniversary of when it was registered and every 12 months after that.
  • You can have a car tested up to one month, minus a day, before the current certificate runs out and still keep the old renewal date.
  • Driving a car without a valid MOT could mean a driving ban, a fine of up to £2,500 and three penalty points on your licence.
  • Even if you are driving to a garage to get your car repaired, you can still be fined if the police consider it dangerous.


What's tested in the MOT?

What an MOT tests

Any features that make the car:

  • safe to drive
  • safe for other road users and
  • safe for the environment

This means lights, brakes, steering, seatbelts, body structure, exhaust emissions and even the drivers' view of the road.

What an MOT does not test

  • The condition of the engine, clutch or gearbox. So don't think of it as a car inspection/service on the cheap.
  • Panels such as plastic sills and engine undertrays are not removed in the test. These can trap moisture and cause rust, which wouldn't necessarily be spotted by the tester.


How does an MOT test work?

Since May 2018, faults have been classified under three different labels: minor, major and dangerous.

  • Minor faults, previously known as ‘advisories’, represent potential safety risks, but will not prevent the car from passing its MOT.
  • Major faults represent a significant safety risk and will result in a ‘fail’, but it will still be possible for you to drive the car from the MOT centre to a garage for repairs (if the MOT centre cannot undertake the work).
  • Dangerous faults are considered such a safety risk that you will not be able to drive the car until they are fixed; this may mean you’ll have to get it towed to a garage for remedial work.

By way of example, a steering mechanism with a slight oil leak would be classed as a minor fault, but if it was dripping oil, that would be a major. If the steering wheel was in danger of becoming detached, meanwhile, that would be flagged as a dangerous fault.

The intention here is to give owners a clearer idea as to the seriousness of the car’s faults. The term ‘dangerous’ is also in line with the Road Traffic Act which says that driving a vehicle in a dangerous condition is a criminal offence.


How is the current MOT different from the previous one?

  • Under the old rules, the items that caused a car to fail were simply marked as ‘failed’. If a fault was not considered to be serious but still a potential safety risk, it was described as an advisory, but didn't cause the car to fail.
  • The test is now also tougher on diesel particulate filters (DPFs), which are devices designed to trap and destroy exhaust particulates. They became mandatory on diesel cars in 2009, although some cars were fitted with them before then. Testers will refuse to test a car if they believe the DPF has been removed or tampered with.
  • Any DPF fitted that emits ‘visible smoke of any colour’ from the car’s exhaust is considered a major fault and constitutes a fail.


What are the most common failures?

Lights lead the list at 30% of failures, followed by tyres at 10%, brakes at 9.6%, and the windscreen, wipers and mirrors at 8.5%. With this in mind, you may want to check these elements ahead of the MOT yourself if you are able to, or arrange a service and have them checked at the time, to avoid failing the MOT and having to get the car booked in again.


How can I check a car’s MOT status?

Visit the government’s MOT status check website and enter the car’s registration. This should give you a rundown of any faults flagged in the previous MOTs - covering more than a decade. Be aware that if you're buying a car and it has - or has had - a private number plate it may show up linked to that private registration or on the original registration depending on whether the seller has swapped them over with the DVLA.

If in doubt, ask for both and check both to see which applies on the MOT system, which shows the number plate and the car model (though there is no guarantee the seller hasn't moved the number plate from one model to a new version of the same car). Again, check with the seller to be sure if you're considering buying the car.

When deciding which used cars are worth considering, checking the MOT history can provide an indication of how well a car has been looked after. If a car has had low tyre tread flagged as an advisory one year and a major fault the next, or the same range of issues keep reappearing year after year, the driver may have neglected the car's maintenance and it's possible that car has more faults that aren't yet visible yet, compared with one that has very few issues flagged.


What if my car fails the MOT test?

You’ll be given a ‘refusal of an MOT certificate’, which will be recorded on the MOT database. If the current MOT is still valid, you can drive the car away but if it has run out, you can only drive it to a garage to have the defects rectified (the garage that did the MOT might be able to fix the car on site), and then to a partial or full re-test.

The retest is free but only if certain components are retested by the same test centre within 24 hours. If the car is retested within 10 days it will only need a partial retest but there may be a charge at the discretion of the test centre.

You can appeal a fail, but first, discuss any problems with the test centre. If you’re still not satisfied, visit the DVSA complaints website and complete the online form.


Can I be fined for driving a car that has failed its MOT?

Although you are permitted to drive your car to a garage to have it repaired before retesting (provided it doesn’t have a ‘dangerous’ fault), you could still be fined up to £2,500 for driving a car on the road in an unroadworthy condition, so it’s probably safer to leave the car with the garage that tested it, for repair.


What if I don't have my car tested?

You are not able to take it on the road unless you are driving to a garage for repairs, or to the test centre. If you are caught driving without an MOT, you could be fined up to £1,000.

Even if you are driving to a garage to get your car repaired, you can still be fined if the police consider it dangerous. See below.


Does my car need servicing if it has an MOT?

Yes. The MOT focuses on areas critical for safety, while a service is designed to keep your car running smoothly and reliably.

Servicing may involve changing air filters or replacing oil, which both help cars to run at their best. Neither of these is covered by an MOT. Getting your car serviced on schedule is often required by your lender if you have a car on finance, too. If you own your vehicle, then regular servicing will make it a more attractive purchase for future buyers, too.


How do I spot an MOT test centre?

Garages that are licensed for MOT testing advertise the service widely. They also display the official blue sign with three white triangles (below).

The government also keeps a log of active MOT test stations, which can be found online.


What happens if my car passes the test?

You’ll be given a certificate while the pass will be recorded on the MOT database. You are then free to drive the car legally for the next year, provided other substantial faults don't materialise.


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