The short answer

Winter tyres are not required by law anywhere in the UK, and nothing in the Highway Code mentions them. The requirement the Code does set, in Annex 6, is that every tyre on a car has at least 1.6 mm of tread across the central three-quarters of its width and all the way round, and is inflated to the maker's figure for the load. That applies in July and in January, to summer, all-season and winter tyres alike. Fall short on a tyre and, as the Met Office's own checklist puts it, you risk a fine of up to £2,500 and three penalty points per tyre, as the page read on 3 November 2026.

So the decision is practical, not legal. If you live where frost, snow and untreated roads are part of most winters, a winter set earns its keep. If you drive salted main roads in a mild city, the money is usually better spent on four good tyres with plenty of tread.

What the law actually requires of a tyre

The Highway Code's vehicle maintenance annex sets two rules for cars. Tread depth MUST be at least 1.6 mm across the central three-quarters of the breadth of the tread and around the entire circumference. Pressure MUST match the manufacturer's specification for the load being carried, and the Code says to check it weekly, before a journey, with the tyres cold. The GOV.UK endorsement codes list using a vehicle with a defective tyre as code CU30, three points, which stay on the record for four years.

Nothing there says what the tyre must be made of or what the weather is doing. A winter tyre worn to the legal limit is as illegal as any other, and a summer tyre with deep tread is legal in a blizzard, however poorly it grips. The Met Office adds a sensible margin above the law: ideally at least 3 mm of tread in icy or very wet conditions, because stopping distances grow as tread shrinks.

What a winter tyre is and what the symbol means

A winter tyre uses a softer rubber compound that stays flexible in the cold, and a tread cut with many small slits, called sipes, that bite into snow and clear water and slush. Tyre makers publish a temperature below which they say the compound outperforms a summer tyre; there is no official UK source for that figure, so we do not quote one. The practical version is that winter tyres work best in weeks of frost, not on the odd cold morning.

The mark to look for on the sidewall is a three-peak mountain outline with a snowflake inside it. It means the tyre has passed a snow-traction test against a reference tyre. An older mark, the letters M and S for mud and snow, is a maker's own description with no test behind it. A tyre with the mountain and snowflake is a tested winter or all-season tyre; one with only M and S may be nothing of the sort.

Who gains and who does not

A winter set makes the most difference to drivers who meet packed snow, ice and untreated side roads, or who have to get to work whatever the forecast: rural commuters, hill villages, anyone north of the mild zone or on a shift pattern that starts before the gritters. It makes the least difference to drivers on treated urban roads in a mild winter, who may go a whole season without a morning the tyres would have changed.

Two things to weigh before you buy. A winter set needs somewhere dry to store the summer set, and a second set of wheels or two fitting sessions a year. And a winter tyre on a warm, dry spring day wears faster and grips less than a summer tyre, so leaving them on until June costs you in both.

All-season tyres, the middle path

An all-season tyre with the mountain-and-snowflake mark is the compromise most UK drivers who want more winter grip end up with: one set, fitted all year, tested for snow, and better than a summer tyre in the cold without being as good as a true winter tyre in deep snow or as good as a summer tyre in a heatwave. If the choice is between a worn summer set and a fresh all-season set this month, the fresh set wins on tread alone.

Whatever you fit, the checks are the same. Tread above the legal limit on every tyre, with the Met Office's 3 mm as the margin to aim for in winter. Pressures to the figure on the door pillar or in the handbook, checked cold. No cuts, bulges or exposed cord. And the spare, if you have one, checked too, or the repair kit found and understood before you need it on a verge in the dark.

What this does not mean

Tyres are the fault family that fails MOT tests at roughly the same rate at every age, which says the problem is wear and neglect rather than the age of the car; our tyre faults piece has the figures and this article has none. A winter tyre does not shorten the gap the Highway Code tells you to leave on ice, which can be ten times the dry-road distance, and it does not make a car stop on sheet ice. Drive slowly in a high gear, brake and accelerate gently, and treat light steering and silent tyres as the warning they are. If you are taking the car abroad this winter, rules on winter equipment differ by country; check the GOV.UK travel advice for the country before you go.

Frequently asked questions

No. No UK law or Highway Code rule requires them. The law that does apply to every tyre all year is the tread and pressure rule in Annex 6 of the Highway Code: at least 1.6 mm of tread across the central three-quarters and all the way round, and pressure to the maker's specification.

The Met Office's vehicle checklist puts it at a fine of up to £2,500 and three penalty points per tyre, as the page read on 3 November 2026, and GOV.UK lists the offence as code CU30, three points, on the record for four years. Four worn tyres are four offences.

That the tyre has passed a snow-traction test against a reference tyre and can be sold as a winter or all-season tyre. The letters M and S alone are a maker's own description with no test behind them. Look for the mountain outline with the snowflake inside if winter grip is what you are paying for.

For most UK drivers on treated roads, an all-season tyre with the mountain-and-snowflake mark is the practical choice: one set, no storage, tested for snow. A true winter set still does better in deep snow and sustained cold, so rural and upland drivers may prefer two sets. Either way, tread depth and pressure matter more than the label.

Sources and method

This article contains no MOT statistics. The tread and pressure rules are quoted from the Highway Code on GOV.UK, the per-tyre penalty from the Met Office vehicle-checks page and the endorsement code from GOV.UK, as those pages read on 3 November 2026. No temperature threshold is quoted because no official source gives one. The MOT reliance notice below applies to the MOT history this site refers to elsewhere.

About these figures. GOV.UK and Met Office content reproduced in summary under the Open Government Licence v3.0. SortedCars is not the DVSA, the DVLA or the Met Office; the links above go to the official pages. Where MOT statistics appear on this site they are computed from the DVSA anonymised MOT results dataset. No figure is shown for any group with fewer than 500 tests. Test class 4 only, first tests only; retests are excluded. Pass rates describe fleets, not individual machines: they reflect how cars were driven, maintained and used as well as how they were built, and beyond recorded mileage none of that is in the data. A well-kept example of a model with a weak average can still pass; a neglected example of a strong one can still fail. Alias spellings of a make are counted under one make name and all trims of a model under one model name, using SortedCars' grouping tables.

This article is general information drawn from published test records. It is not professional, mechanical or legal advice, and an MOT pass or a clean MOT history does not guarantee that a car is roadworthy today. If you are unsure about a car, have it inspected by a qualified mechanic. You can check any vehicle's MOT history free on the official GOV.UK MOT history service.

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