Every Illegal Tyre Now Risks Drivers a £2,500 Fine and Three Penalty Points

• The legal minimum tyre tread depth in the UK is 1.6mm across the central three-quarters of the tyre and around its full circumference.
• Each illegal tyre carries its own £2,500 fine and three penalty points, so four bald tyres can add up to £10,000 and 12 points from one roadside stop.
• Twelve points triggers an automatic six-month driving ban under the totting-up rules, and new drivers lose their licence entirely at just six.

Check the 20p Coin Test Before You Check Anything Else

Push a 20p coin into the main grooves of each tyre. If the outer rim of the coin disappears into the rubber, the tyre clears the legal minimum. If the rim stays visible, the tread has worn below 1.6mm and the tyre is illegal to drive on. That check takes under a minute per tyre and costs nothing, and it is the single most useful thing a driver can do before a long trip, an MOT, or simply this weekend.

The 1.6mm limit applies across the central three-quarters of the tyre’s width and around its entire circumference, not just at one point. A tyre can look fine on the outer edge and still be illegal in the centre, which is why a single glance from the driver’s seat is not enough. Uneven wear from poor tracking or under-inflation often hides a problem exactly where a quick visual check would miss it.

The Penalty Is Per Tyre, Not Per Car

Police can issue a fixed penalty of up to £100 and three penalty points for each illegal tyre found on a vehicle, and the maximum court fine is £2,500 per tyre. Because the penalty is applied per tyre rather than per vehicle, a car stopped with all four tyres below the legal limit faces a theoretical maximum of £10,000 in fines and 12 penalty points from a single roadside check.

Twelve points is enough to trigger an automatic six-month driving ban under the totting-up procedure that applies once a licence reaches 12 or more points within three years. New drivers face a harder threshold. Anyone still in the two-year probationary period after passing their test loses their licence automatically at six points, meaning two illegal tyres from one check could end a new driver’s ability to drive at all, pending a full retest.

Why Tyres Fail Faster Than Drivers Expect

Front tyres on a front-wheel-drive car typically wear faster than the rears, since they carry the weight of the engine and do the steering and most of the braking. A tyre that measures comfortably legal at an MOT eight months ago can drop below 1.6mm well before the next test, particularly on a car doing high motorway mileage or one that has gone without a wheel alignment check.

Under-inflation accelerates the problem. A tyre running even a few PSI below the manufacturer’s recommended pressure wears unevenly across its width, which means the centre or the edges can fall below the legal limit while the rest of the tyre still looks acceptable. Checking pressure monthly, when the tyres are cold, catches this before it becomes a wear problem rather than after.

What Counts as an Illegal Tyre Beyond Tread

Tread depth is the most common check, but it is not the only thing that makes a tyre illegal. A cut or lump in the sidewall that exposes the cords underneath, a bulge from impact damage, or a tyre fitted the wrong way round for its tread pattern can all result in the same fine and points as worn tread. Mixing radial and cross-ply tyres on the same axle is also illegal, though this is now rare on modern cars.

Part-worn tyres bought secondhand carry a particular risk. A police sting on part-worn tyre sellers found every single tyre checked broke the law in some way, whether on tread, damage, or incorrect labelling of the tyre’s condition. A tyre that looks like a bargain on a part-worn seller’s forecourt can already be sitting close to the legal limit before it has even gone through a single winter on the buyer’s car.

What to Do Right Now

Check all four tyres with a 20p coin at several points around the circumference, not just one spot. If any tyre is close to the limit, get a proper tread depth gauge reading from a tyre shop, which most will do for free, and ask for the actual millimetre figure rather than a verbal opinion. Replacing a tyre at 2mm rather than waiting until it fails a check is a planned cost; a roadside fine is not.

If four tyres are all approaching the limit together, budget for a full set rather than replacing one at a time, since mismatched tread depths on the same axle can affect handling and are themselves subject to guidance from tyre manufacturers. Keep the receipt and the old tyre’s DOT date code if a dispute over a part-worn purchase arises later, since that code proves how old the tyre actually was when it was sold.

How Roadside Checks Actually Catch This

DVSA and police roadside checks routinely include a visual tyre inspection alongside brakes, lights and general condition, and tyre defects remain one of the most common reasons a vehicle fails an unscheduled check outright. A recent round of DVSA roadside enforcement on vans and light commercial vehicles found roughly 70 percent had at least one mechanical fault serious enough to warrant a prohibition, with tyre condition among the most frequent issues identified. Private cars are stopped less often for planned checks than commercial vehicles, but the same inspection standard applies whenever an officer does pull a car over, whether the original reason for the stop was tyres or something else entirely.

An officer does not need a specialist tread depth gauge to issue a fixed penalty. A visual assessment that the tread appears close to or below the legal limit is enough to justify further inspection at the roadside, and a gauge reading confirming the defect is usually taken on the spot before any penalty is issued. This means a driver cannot argue after the fact that the measurement was inaccurate without evidence of their own taken before the stop.

The MOT Connection Most Drivers Miss

A car can pass its MOT with tyres sitting only slightly above the legal minimum, since the test checks compliance on the day rather than how much life is left in the tyre. A pass certificate showing tyres at 1.8mm gives a driver almost no buffer before the tread drops below the legal 1.6mm limit, particularly if the car covers significant motorway mileage between test dates. DVSA data on the most common reasons cars fail their MOT consistently places tyre condition among the top defect categories, alongside lighting and suspension faults, which shows how frequently tyres are already borderline by the time a car reaches its test date.

Checking the tread depth figure recorded on the most recent MOT certificate, available for free through the government’s MOT history checker using a car’s registration number, gives a useful early warning. A car that passed with tyres just above the limit needs checking again well before the next annual test, not left until the following MOT to find out whether it has quietly become illegal in the meantime.

Winter Makes the Risk Worse

Tread depth does more than keep a tyre legal, it directly affects how well a car can disperse water and maintain grip in wet and cold conditions, which is exactly when the consequences of driving on worn tyres are most dangerous. Stopping distances increase sharply as tread depth falls, even before a tyre reaches the legal minimum, which means a tyre that is technically still legal at 2mm can already be performing significantly worse than a new tyre in heavy rain. Drivers heading into autumn and winter conditions face both a higher chance of a defect being spotted at a routine stop and a higher real-world safety cost if they choose to delay replacement.

Sources:

• GOV.UK, The Highway Code and tyre legal requirements
• RAC Drive, Tyre tread depth: UK law and safety checks
• DVSA, Motoring offences and penalty points guidance