MOT Advisory vs Failure: What's the Difference? (2026)

The Four MOT Defect Categories

On 20 May 2018, the UK introduced a new MOT defect classification system to align with EU Directive 2014/45/EU. The old system had just two outcomes: "Advisory" or "Fail". The new system introduces more granularity by splitting defects into four categories based on severity. Here is what each one means.

Category	MOT Result	Can You Drive?	Action Required
Advisory	Pass	Yes	Monitor and repair when convenient
Minor	Pass	Yes	Repair as soon as possible
Major	Fail	Only to a garage for repair*	Must repair before certificate issued
Dangerous	Fail	No — do not drive	Must repair immediately before driving

* If the previous MOT certificate is still valid, you may drive to a garage for repair. If the MOT has expired, you may only drive to a pre-booked MOT appointment.

Advisory: "Monitor and Repair if Necessary"

An advisory notice is issued when the inspector identifies a component that is beginning to deteriorate but has not yet reached a level that affects the vehicle's safety or roadworthiness. The vehicle passes the MOT and you receive a full certificate. Advisories are recorded in the DVSA database and appear on the vehicle's MOT history.

Common Examples of Advisory Notices

Brake disc worn, pitted, or scored, but not to the point of failure
Tyre tread depth approaching but not below the 1.6mm legal minimum
Front suspension arm bush slightly deteriorated but no excessive movement
Brake pad friction material wearing thin but still above minimum
Slight oil leak that has not reached the exhaust or other hot components
Exhaust mounting slightly corroded but still secure
Minor corrosion on a body panel that is not structural

Key takeaway: Advisories do not prevent you from driving, but they are early warning signs. Items flagged as advisories on consecutive MOTs suggest the owner has been ignoring progressive wear — a red flag for used car buyers.

Minor Defect: "Repair as Soon as Possible"

A minor defect is a step up from an advisory. It means the component has deteriorated beyond the advisory threshold but has not yet reached the point where it poses a significant safety risk. The vehicle still passes the MOT, but you are expected to have the defect repaired promptly. Minor defects are recorded on the MOT certificate and in the DVSA database.

Common Examples of Minor Defects

Number plate slightly damaged but still legible
Headlight aim slightly out but not excessively
Wiper blade slightly deteriorated but still clears the screen
Exhaust has a small blowing joint but is otherwise secure
Rear reflector slightly faded or discoloured
Slight play in a steering component that is not excessive

Key takeaway: A minor defect means the vehicle passed, but the issue should be repaired soon. If left, it will almost certainly become a major failure by the next test.

Major Failure: "Repair Immediately"

A major defect means the vehicle has failed the MOT. The defect has a significant effect on the vehicle's safety or a direct effect on the environment. The vehicle must be repaired and retested before a new MOT certificate can be issued. You receive a VT30 refusal of MOT test certificate listing all the major (and dangerous) defects found.

Common Examples of Major Failures

Headlight not working or badly aimed
Brake efficiency below the minimum 58% threshold
Tyre tread depth below 1.6mm
Tyre with a bulge, exposed cord, or deep cut
ABS warning light permanently illuminated
Airbag (SRS) warning light not working or permanently on
Engine management light (EML) on during emissions test
Excessive steering play or worn track rod end
Windscreen crack greater than 10mm in Zone A or 40mm in the swept area
Broken coil spring
Significantly corroded structural member
Diesel Particulate Filter (DPF) removed
Catalytic converter tampered with or removed

Key takeaway: A major failure means the vehicle does not meet the minimum legal standard for road use. If your previous MOT is still valid, you can drive to a repair garage. If it has expired, you can only drive directly to a pre-booked MOT test.

Dangerous Defect: "Do Not Drive Until Repaired"

A dangerous defect is the most severe category. It means the vehicle is a direct and immediate danger to the driver, passengers, or other road users. The vehicle fails the MOT and must not be driven under any circumstances until the defect is repaired. This is the only defect category where you are legally prohibited from driving the vehicle at all — even to a repair garage.

Common Examples of Dangerous Defects

Brake component so worn or damaged that the vehicle cannot stop safely
Tyre with visible cord or structural damage that could cause sudden deflation
Steering component at the point of disconnection
Structural member so corroded it could collapse under load
Fuel leak onto hot components creating a fire risk
No brake lights at all
Wheel bearing with excessive play that could cause wheel detachment
Seat or seatbelt mounting so weakened by corrosion it offers no restraint

Key takeaway: A dangerous defect means the vehicle is an immediate danger to anyone on the road. You must not drive it. Have it repaired at the test centre, towed to a garage, or repaired on-site before moving it.

How Defect Categories Affect Used Car Buying

MOT history is one of the most valuable free tools when buying a used car. Here is what to look for when reviewing a vehicle's defect history:

Repeated advisories on the same component suggest the owner has been ignoring progressive wear. For example, "brake pad wearing thin" appearing year after year means the brakes have been neglected.
Multiple major failures across different tests indicate poor maintenance. A single failure is normal over a car's lifetime, but a pattern of failures is a red flag.
Any dangerous defect in the history deserves scrutiny. It means the vehicle was in a condition that made it immediately dangerous to drive. Check whether the defect was properly repaired and whether similar issues have recurred.
Advisory items approaching failure threshold help you budget for upcoming repairs. If the last MOT showed "tyre tread depth approaching minimum", you know new tyres will be needed soon.

Check Any Vehicle's MOT History

Enter a registration number to view the full MOT history including every advisory, minor defect, major failure, and dangerous item recorded against the vehicle since 2005.

Free MOT Check

Frequently Asked Questions

Do MOT advisories go on record?

Yes. All advisory notices are recorded on the MOT test result and stored in the DVSA database. They appear on the vehicle's MOT history and are visible to anyone who checks using the registration number. This means prospective buyers can see past advisories, making it important to address them before selling a vehicle.

Can I still drive with an MOT advisory?

Yes. Advisory items do not affect your MOT certificate — the vehicle has still passed. However, an advisory indicates that a component is beginning to deteriorate, so you should monitor it and plan for repair. Ignoring advisories can lead to the item becoming a major failure at the next test, or potentially causing a safety issue before then.

What happens if I get a dangerous defect on my MOT?

If a dangerous defect is found, the vehicle fails the MOT immediately and you are legally prohibited from driving it until the defect is repaired. The DVSA considers a dangerous defect to be a direct and immediate risk to road safety or the environment. Driving a vehicle with a known dangerous defect is an offence and your insurance may be invalidated.

How long do I have to fix an MOT failure?

There is no fixed deadline to repair an MOT failure, but you cannot legally drive the vehicle on public roads without a valid MOT certificate (except directly to a pre-booked MOT test or to a repair garage if the failure is not 'Dangerous'). If you have the repair done at the same test centre within 10 working days, you are usually entitled to a free or partial-fee retest.

Can a minor defect become a major failure?

Yes. Minor defects are items that are deteriorating but have not reached the failure threshold. If left unrepaired, they will typically worsen and become a major failure at the next MOT test. For example, a minor defect for 'brake pad wearing thin' will become a major failure once the pad material is below the minimum thickness.

What is the difference between the old and new MOT defect system?

Before May 2018, MOT defects were simply classified as either 'Advisory' or 'Fail'. From 20 May 2018, the system was updated to align with EU Directive 2014/45/EU, introducing four categories: Advisory (monitor), Minor (repair soon), Major (fail — repair required), and Dangerous (fail — do not drive). The new system provides more granularity about the severity of each defect.

Does an advisory affect my car insurance?

No. MOT advisories do not need to be declared to your insurer and do not affect your premium. However, if an advisory item causes an accident because you failed to repair it (for example, severely worn tyres that were previously flagged), your insurer could argue that the vehicle was not roadworthy and refuse to pay out on a claim.