Key takeaways
- Driving on an illegal tyre risks a fine of up to £2,500 and 3 penalty points — per tyre, per gov.uk.
- Four illegal tyres in the worst case means up to £10,000 in fines and 12 points, enough to lose your licence.
- The legal minimum tread is 1.6mm across the central three-quarters and all the way round.
- Mixing certain tyre types on the same axle, running them under-inflated or with visible damage can all break the law.
- Tyre defects are among the most common MOT failures, so the cheapest fix is to catch them early.
Tyres are the only part of your car that touches the road, so the law sets clear rules on how worn, damaged or mismatched they can be. Break those rules and the penalties are steep — and they stack up tyre by tyre. This guide explains exactly what UK tyre law requires, what it costs if you ignore it, and the everyday situations that quietly make a tyre illegal.
What are the penalties for illegal tyres in the UK?
According to gov.uk, using a vehicle with a defective or illegal tyre carries a fine of up to £2,500 and 3 penalty points per tyre. The penalty applies to each non-compliant tyre separately, so the figure is not a one-off — it multiplies. The police can issue a fixed penalty roadside or refer the matter to court for the maximum amounts.
This is one of the harshest penalty structures in everyday motoring law, precisely because worn tyres dramatically increase stopping distances in the wet. The points sit on your licence for four years and can push insurance premiums up sharply.
How bad is the worst-case scenario?
In the worst case — all four tyres illegal at once — the penalties reach up to £10,000 in fines and 12 penalty points. For most drivers, 12 points within three years means an automatic disqualification, and new drivers can lose their licence at just 6 points within two years of passing.
| Illegal tyres | Maximum fine | Penalty points |
|---|---|---|
| 1 tyre | £2,500 | 3 points |
| 2 tyres | £5,000 | 6 points |
| 3 tyres | £7,500 | 9 points |
| 4 tyres | £10,000 | 12 points (likely ban) |
What is the legal tread depth?
The legal minimum tread depth in the UK is 1.6mm, measured across the central three-quarters of the tyre and around its entire circumference. This is set out in the Highway Code (rule 89) and applies to cars, light vans and light trailers. If any part of that central band drops below 1.6mm, the tyre is illegal — even if the rest looks fine.
Most manufacturers and TyreSafe recommend replacing at around 3mm, because wet braking falls away noticeably below that point. The last 1.4mm of legal tread is also the least safe. You can confirm depth quickly with the 20p tread test or a cheap gauge.
Can mixing tyre types break the law?
Yes. UK regulations restrict mixing certain tyre constructions on the same axle. You must not fit a cross-ply and a radial tyre together on the same axle, and you cannot mix a bias-belted tyre with a radial in some combinations. Fitting mismatched tyres in these ways can make the vehicle illegal and unsafe to handle.
Beyond the strict legal restrictions, it is poor practice to mix significantly different tread patterns, brands or wear levels across an axle, because grip becomes unbalanced. If you only need to replace two tyres, fit the matching pair across the same axle.
Do under-inflation and damage count as offences?
They can. A tyre that is not "maintained in such condition as to be fit for the purpose" — including being seriously under or over-inflated for its load — can be treated as defective. So can a tyre with a cut or bulge, exposed cords or ply, lumps or a tyre that is not properly seated on the rim.
- Cuts and bulges — a sidewall bulge means internal damage; the tyre is illegal and must be replaced. See sidewall damage.
- Exposed cords or ply — any visible structural fabric fails both the law and the MOT.
- Under-inflation — runs the tyre too hot, wears the edges and can be cited as unfit.
- Wrong load or speed rating for the vehicle can also be an offence.
Are there rules on the spare tyre and load rating?
Yes. If a spare or space-saver is fitted and in use, it must also meet the legal requirements while on the road, including the 1.6mm minimum tread for a full-size spare. Every tyre must additionally carry a load index and speed rating at least as high as the vehicle manufacturer specifies, so fitting an under-rated tyre is itself an offence.
A space-saver has its own speed limit (commonly 50mph) marked on it, and driving above that is unsafe and can void the maker's guidance. If you are unsure what your spare can do, our guide to the spare tyre vs space-saver difference explains the limits.
Tyres and the MOT
Tyre faults are checked at every MOT and are among the most common reasons cars fail, per DVSA test data. The tester inspects tread depth, condition, correct fitment and, on cars first used from 2012, the tyre pressure monitoring system (TPMS). A TPMS warning that stays on is an automatic MOT failure on those cars.
Because the same faults that fail an MOT are the ones that get you fined on the road, a quick monthly check pays off twice. Browse the most common issues in our guide to common tyre MOT failures.
It is also worth remembering that the MOT certificate is not a defence on its own. The legal duty to keep tyres roadworthy is continuous, so a tyre that passed months ago can become illegal through normal wear or a single pothole. Treat the MOT as a starting point, not a year-long guarantee, and keep checking between tests.
How do penalty points and your licence work?
Penalty points for defective tyres stay on your driving record for four years and count towards the totting-up thresholds. Accumulate 12 points within three years and most drivers face an automatic ban of at least six months; newer drivers can lose their licence at just 6 points within two years of passing their test.
Because each illegal tyre can add 3 points, it is genuinely possible to reach a ban from a single roadside stop if several tyres are below the limit. Add the insurance increase that follows an endorsement and the true cost of a worn tyre is far higher than a replacement would ever be.
Staying legal without the hassle
If a check turns up a tyre below 1.6mm, a sidewall bulge or a mismatched pair, it should not be driven. Rather than risk an illegal tyre on the way to a garage, Fast Tyre's mobile tyre fitting brings the right tyres to your home, work or the roadside across London and central England, usually within 30 to 60 minutes, and fits them on the spot. Send a photo on WhatsApp if you are unsure whether a tyre is legal.
Frequently asked questions
Per tyre. Each illegal tyre is a separate offence carrying up to £2,500 and 3 penalty points, so two illegal tyres can mean up to £5,000 and 6 points, and four can reach £10,000 and 12 points — enough to lose your licence.
No. The £2,500 is the court maximum. A roadside fixed penalty is usually lower, but the penalty points still apply and several defective tyres can be cited at once, so the combined total and points can still be serious.
Yes. An MOT is a snapshot on the test day. Tyres wear and can be damaged at any time afterwards, so a tyre that passed months ago can still be illegal today. The legal duty to keep tyres roadworthy is continuous.
Mixing brands is not automatically illegal, but you must not mix cross-ply and radial tyres on the same axle. It is best practice to fit matching tyres across an axle for balanced grip, even where the law allows otherwise.
It can. A tyre seriously under-inflated for its load may be treated as not fit for purpose and therefore defective. Under-inflation also wears the tyre edges, raises fuel use and increases the risk of a blowout.
Almost always. Endorsements for defective tyres stay on your licence for four years and insurers can raise premiums or refuse cover. With multiple tyres cited, the points and cost increase, which is why early replacement is far cheaper.