An MOT failure means your car is unroadworthy and illegal to drive. An advisory item isn't a failure, but a DVSA-recorded warning that a part is wearing out and will need attention soon to remain safe and legal.
Every year, millions of us take our cars for their MOT test, and for many, the final certificate can be a bit confusing. You either pass or you fail, right? Well, it's a little more complicated than that. You might get a pass certificate that comes with a list of 'advisory items', or even 'minor defects', leaving you wondering what they actually mean. It’s one of the most common questions I get asked: "What's the real difference between an MOT advisory and a failure?" Understanding this difference is absolutely critical. A failure (a 'major' or 'dangerous' defect) means your car has not met the minimum legal standard of roadworthiness and there are strict rules about whether you can drive it. An advisory, on the other hand, is a heads-up from the tester. It's me, the examiner, telling you that while a component has passed the test today, it's getting worn and will likely need replacing before your next MOT. Getting to grips with these categories isn't just about passing the test; it's about understanding the actual safety of your vehicle. The MOT isn't just a box-ticking exercise; it's a vital safety inspection designed to keep dangerous cars off the road. Let's break down exactly what the rules are, how I make the call during an inspection, and what you should do with the information you're given.
The official UK MOT rule
Right, let's get into the rulebook. Everything we do as MOT testers is governed by the Driver and Vehicle Standards Agency (DVSA). Our bible is the 'MOT Inspection Manual', which lays out the procedures and standards for every single part of the test. When we find an issue with a vehicle, we have to categorise it according to Section I ('Introduction') of this manual. There are three main defect categories you need to know about: * **Dangerous:** This is the most serious category. The manual states a defect is 'dangerous' if it "has a direct and immediate risk to road safety or has a serious impact on the environment." If your car has a dangerous defect, it fails the MOT, and a big red warning is printed on the certificate. Crucially, you are not legally allowed to drive the vehicle away from the test centre, or anywhere else, until that defect is repaired. The only exception is if it's driven to a pre-booked repair appointment at another garage, but even that is a grey area that many would advise against. Driving a vehicle with a dangerous defect can land you with a hefty fine and points on your licence. * **Major:** A 'major' defect is one that "may affect the vehicle’s safety, put other road users at risk or have an impact on the environment." This will also cause the car to fail its MOT. Your VT30 'Refusal of an MOT Test Certificate' will list any majors. Unlike a dangerous defect, you *may* be able to drive the car away, but only if your previous MOT certificate is still valid and the defects themselves aren't deemed dangerous. You can drive it to a garage for repair or a pre-booked retest. If your old MOT has expired, you can only drive it to that repair appointment or retest. * **Minor:** This is where it gets interesting. A 'minor' defect is an issue where "there is no significant effect on the safety of the vehicle or impact on the environment." A car with only minor defects will *pass* the MOT. These items are recorded on your pass certificate (the VT20) a
How testers actually assess this
The manual gives us the rules, but a lot of the job comes down to experience and judgement. When I'm under a car in the inspection bay, I'm not just looking for things that have broken; I'm looking for things that are *about* to break. It's a process of mechanical analysis, not just a checklist. Let's take a common example: corrosion on a brake pipe. The manual tells me that a brake pipe is a failure if it's "excessively corroded". But what does 'excessively' mean? If I see light surface rust, that's completely normal on a car of a certain age. I might add an advisory: "Nearside front brake pipe corroded but not seriously weakened". This tells you, the owner, to keep an eye on it. However, if I can see deep pitting, flaking, or if the pipe feels rough and I suspect its structural integrity is compromised, that immediately becomes a Major defect, and a fail. I have to physically and visually assess it and make a professional judgement based on my training and a couple of decades of seeing what happens to pipes like that over time. It's the same with suspension components. I'll use a long pry bar to check for movement in ball joints and suspension bushes. The manual gives us a simple rule: 'excessive movement'. Again, this is where experience is key. A tiny bit of barely perceptible play in a ball joint on a high-mileage car might warrant an advisory. It's not perfect, but it's not yet dangerous. But if I can feel a definite 'clunk' or see significant movement, that's a Major fail. It’s a sign the joint is worn out and could potentially fail under heavy cornering or braking loads. For something like a shock absorber, a light 'misting' of oil around the main seal is quite common. It’s not ideal, but the shock is still working. I'd almost always list that as an advisory. However, if oil is clearly dripping from it or the unit is covered in a thick layer of oily dirt, it has obviously lost a significant amount of fluid and its damping ability is compromised. That's a Maj
Common scenarios — pass, advisory or fail?
To make this even clearer, let's walk through some real-world examples that I see every week in the test lane. Seeing how the same component can fall into different categories should help you understand our thought process. ### Scenario 1: Tyres Tyres are one of the most common MOT items, and the rules are quite clear. * **Pass:** The tyre has more than 3mm of tread across the central three-quarters of its width, with no cuts, lumps, or bulges. * **Advisory:** The tread is measured at 2.0mm. The legal limit is 1.6mm, so it's a pass. But it will wear to the legal limit very soon, so I'll advise it. Another common advisory is "Tyre slightly perished on sidewall" – this means small surface cracks are appearing due to age, but they're not deep enough to be a structural risk yet. * **Fail (Major):** The tread depth is 1.5mm. It's below the legal minimum, so it's an immediate fail. Or, there's a lump or bulge on the sidewall, which indicates structural failure and a high risk of a blowout. * **Fail (Dangerous):** There is a deep cut on the tyre that is so severe the internal cords are exposed. This means the tyre's structure is critically compromised and could disintegrate at any moment. ### Scenario 2: Coil Springs Broken coil springs are incredibly common, especially on modern cars navigating potholed roads. * **Pass:** The spring is intact, with no heavy corrosion and its protective coating is mostly there. * **Advisory:** The spring's coating is peeling off and there is heavy surface corrosion. It's not broken yet, but rust is the enemy of springs, and this one is on its way out. * **Fail (Major):** The spring is cracked or has a section broken off. Even if it's just the very tip, it's a fail because the suspension is no longer operating as designed. ### Scenario 3: Exhaust System We test the exhaust for security, leaks, and emissions. * **Pass:** The system is secure, has no major leaks, and passes the emissions test. * **Advisory:** A mounting bracket is slightly co
What to do if you're worried before your test
A bit of pre-MOT anxiety is normal, but you can save yourself a lot of stress (and potentially money) by doing a few simple checks yourself before you bring the car to the garage. You don't need to be a mechanic; this is just about spotting the easy-to-fix things that cause a surprising number of failures. Take 10 minutes to do the 'L-I-T-T-L-E' check: * **L is for Lights:** This is the number one cause of simple failures. Get a friend to help you. Turn on your ignition and check every single exterior bulb. That means headlights (dipped and main beam), sidelights, all four indicators, your brake lights (including any central one), reversing lights, and both front and rear fog lights. A single blown bulb is a Major fail. * **I is for Inside the car:** Check your horn – give it a quick toot. Check your seatbelts – pull them all out fully and check for damage, then make sure they retract properly. Make sure your driver's seat adjusts forwards and backwards. Finally, look at your dashboard when you turn the ignition on. Are any warning lights staying on? A lit-up airbag, ABS, or engine management light (MIL) is a fail. * **T is for Tyres:** Check your tyre pressures. Then, look at the tread. A quick way to check is the 20p test – insert a 20p coin into the main tread grooves. If the outer band of the coin is hidden, your tread is likely legal. If you can see the outer band, it’s probably getting low and you should have it checked properly. Also, run your hands over the surface and look for any cuts, bulges, or objects stuck in the rubber. * **T is for Topping-up:** Your windscreen washers must work. Make sure your screenwash bottle is full, and test that the jets spray cleanly onto the screen. While you're at it, check your wiper blades for any splits or tears. If they leave big smears, they'll likely fail. * **L is for Look and Listen:** Look at your number plates – are they clean, uncracked, and correctly spaced? Look at your mirrors – are the glass and casings intact
What happens if you do fail
Okay, so the worst has happened, and your car has failed its MOT. Don't panic. The first thing you'll receive is a VT30 'Refusal of an MOT Test Certificate'. This document lists the 'Dangerous' and 'Major' defects that caused the failure. Your next steps depend on the type of failure and the status of your old MOT certificate. * **If your car fails with 'Dangerous' defects:** The law is crystal clear. The car is considered a direct and immediate risk to road safety. You **cannot** drive it. It must be repaired at the test centre or recovered by a tow truck to another location for repair. Driving it on a public road is illegal and carries severe penalties. * **If your car fails with 'Major' defects:** This is more nuanced. If your previous MOT certificate has not yet expired, you are legally permitted to drive your car away. However, you should only drive it to a pre-arranged appointment to have the defects repaired, or to a pre-booked MOT retest. If your old MOT has expired, the same rules apply – you can only drive it to get it repaired or retested. You cannot use it for general driving like commuting or shopping. The police can stop you and check the MOT database, so be warned. **Getting a Retest:** You have a period of 10 working days to get the vehicle repaired and retested. How this works depends on where and when you do it: * **Leave it at the test centre:** If you leave the car with the garage that did the MOT for repair, they can carry out a partial retest (just on the failed items) for free for a list of specific items (things like lights, wipers, wheels and tyres). * **Bring it back within one working day:** If you take it away, get it repaired, and bring it back to the *same* test station before the end of the next working day, you can also get a free partial retest for those specific items. * **Bring it back within 10 working days:** If you bring the car back to the *same* test station within 10 working days, a partial retest will be done. This is not fr
Can I just ignore an MOT advisory? — Absolutely not. While an advisory isn't a fail, it's an official DVSA-recorded warning that a part is wearing out. Ignoring it is risky; the component could deteriorate and become dangerous before your next MOT. It will almost certainly become a failure at the next test if left alone. Furthermore, if you were stopped by the police, they can still penalise you for having a vehicle in a dangerous condition (e.g., bald tyres), even if you have a valid MOT certificate with an advisory for it.
Does an MOT advisory affect my car's value? — Yes, it can. All MOT results, including failures and advisories, are logged on a publicly accessible online database. A savvy buyer will always check this history. A car with a clean record is more attractive than one with a long list of advisories, especially if those same advisories appear year after year, suggesting they've been ignored. It can be used as a tool to negotiate the price down, as the buyer knows they will soon have to spend money on those items.
Is a 'Minor' defect the same as an advisory? — They're similar but officially different. A 'Minor' defect is an actual fault that has been found, but it's not considered serious enough to fail the MOT. An example is a number plate light not working, where at least one other remains lit. An 'advisory' is not a current defect; it's a note about a part that is wearing but still within legal limits, like a tyre with 2.5mm of tread. Both are recorded on your certificate to give you a heads-up for future maintenance.
My car passed with advisories. Is it safe to drive? — On the day of the test, yes. To pass the MOT, your car met the minimum legal standard for roadworthiness. However, an advisory is a clear signal from an expert that a component is nearing the end of its life. While it's safe enough 'for now', its condition will worsen over time. You should treat advisories as a 'to-do' list. Plan to have them inspected by a mechanic and rectified in the near future to ensure the car remains safe and to avoid more expensive repairs down the line.