Is my number plate legal?

In Great Britain, number plates must show the registration number correctly. GOV.UK's displaying number plates guide, checked in 2026, says you cannot rearrange letters or numbers, or alter them so that they are hard to read. You could be fined up to £1,000 and the vehicle will fail its MOT if you drive with incorrectly displayed plates. DVLA's INF104 is the official booklet behind that guide. The detailed construction, font and spacing rules live on the number plate rules page, which this car law page does not copy out in full.

The current format, from 2001, is two letters for the region, two numbers for the age identifier, and three random letters. That is how you read the mark, not how you are allowed to restyle it. The mark on the plate has to be the mark on the V5C, in the right order, with the right gaps. Closing the gap to invent a word is the usual offence. So is a non standard font, a tinted plate, or bolts placed to look like extra characters.

GOV.UK says the vehicle will fail its MOT if you drive with incorrectly displayed number plates. The tester also inspects the rear registration plate lamps. Those lamps must light the rear plate, and they must come on with the position lamps. A plate you cannot read after dark is a lighting fail as well as a display fail. Section 4.7 of the DVSA car manual makes a missing or inoperative plate lamp a major defect when it is the only lamp, and a minor defect when at least one of two still works.

A current MOT does not make a later homemade plate legal. Fitting a 'show' plate after the test, then using the car on the road, is using an incorrectly displayed mark. The offence is the display on the journey, not the display in the MOT bay last spring.

Highway Code rule 229 says that before you set off in ice or snow you must ensure that lights are clean and number plates are clearly visible and legible. Annex 6 says lights, indicators, reflectors and number plates must be kept clean and clear. A plate buried in slush is not a legal display. Clear it, including the rear plate lamp, before you move.

A bike rack, a tow ball cover or a trailer that hides the car's rear plate is the same problem with a different cause. When you tow, the trailer must show the car's registration, which is the towing number plate rule. When you carry a rack, the car's own rear plate still has to be visible, or you need a repeater plate that shows the same mark. This page does not invent a repeater-plate specification. If the issued mark cannot be read from behind, the display is wrong.

For ordinary UK towing, the trailer shows the same registration as the towing vehicle. If you tow more than one trailer, GOV.UK says the plate goes on the trailer at the back. A trailer over 750 kg that travels through most European countries also needs its own trailer registration. That is a towing page, not a duplicate of INF104.

Hire cars, company cars and courtesy cars still have to display the mark that belongs to that vehicle. You cannot put your private plate on a hire car for the weekend. Northern Ireland has its own plate format and DVA rules. INF104 and the GOV.UK displaying guide cited here are GB documents. An NI plate on an NI car is a different system. A GB car driven in Northern Ireland still has to display its GB mark correctly.

GOV.UK tells you to use a registered number plate supplier. The supplier needs to see the documents INF104 lists. Theft-resistant plates, which make it harder to remove the plate quickly, are optional and available from dealers and registered suppliers. Personalised marks are a separate assignment process, covered on the private plates page. None of that lets you restyle the characters once the plate is on the car.

Eyesight is the other plate rule people forget. Highway Code rule 92 says you must be able to read a number plate, in good daylight, from 20 metres, or 20.5 metres for an old-style plate. If you need glasses or contact lenses to do that, you must wear them while driving. The police can require an eyesight test. That is not a display offence, but it is why the plate has to stay readable: the whole system assumes the mark can be read.

Stylised fonts, 3D gel digits, tinted film over the plate, and bolts that turn a C into an E. Towing without a matching plate on the trailer. A dirty rear plate lamp so the mark disappears after dark. A bike rack with no repeater. A private plate that has been assigned but never fitted, so the car still shows the old mark, or the opposite: a plate fitted before the assignment has gone through.

The rules page is the place for the millimetre measurements. This page is the place to say: the mark must be the issued mark, it must be readable, it must be lit at the rear, and getting that wrong is both a GOV.UK display offence and an MOT fail. If you need fonts, flags or the British Standard, follow the link. If you need to know what the mark means, use the decoder. If you need to move a private mark, use the private plates page.

GOV.UK states that you could be fined up to £1,000 and that the vehicle will fail its MOT. The officer can also require the plate to be put right, and a prohibition can follow if the vehicle is being used in a condition that is dangerous or that breaks the construction and use rules more widely. This page does not invent extra penalty points for a display offence, because the GOV.UK displaying guide cited here names the fine and the MOT fail, not a points tariff.

ANPR cameras read the mark as issued. A stylised plate that a person can squint at and decode is still a plate the camera may misread, which is how people get notices for a vehicle they do not own, or fail to get a parking ticket that then escalates. The cheap fix is a standard plate from a registered supplier. The expensive fix is arguing about a homemade layout after a notice has already been issued.

INF104 and the GOV.UK displaying guide apply in Great Britain. Wales has a Welsh-language version of the GOV.UK guide. The mark itself does not change at the Welsh or Scottish border. National flags and identifiers on the plate are a construction rule, covered on the rules page, not a different registration system for each nation.

Northern Ireland issues its own format and has its own DVA process. A GB plate on a GB car remains a GB plate when you drive it in Northern Ireland, and it still has to be displayed correctly. Do not mix NI and GB identification systems on the same vehicle. For an NI-registered vehicle, use nidirect and the DVA, not INF104, as the primary document.

For ordinary UK towing the trailer shows the same registration as the towing vehicle, as a proper plate, on the rear-most trailer if you tow more than one. That is a GOV.UK towing equipment rule, and it has its own page under towing. This car law page is about the car's own display. After a private plate change, both the car and the trailer have to show the new mark. A trailer over 750 kg that goes abroad often needs a separate trailer registration as well.

The detailed fonts, flags, British Standard and spacing millimetres remain on the number plate rules guide. Use that guide when you are having a plate made. Use this page when you are checking the car before a journey, next to the lights and the tyres.