Illegal number plates – all you need to know

In the most recent police data, 2020 figures showed that 13,720 drivers were stopped by police for having illegal number plates.

In this guide, we look at what makes a plate illegal, the rules around how to display them, and the penalties for breaking the law.

In the UK, vehicle number plates must adhere to strict regulations set by the Driver and Vehicle Licensing Agency (DVLA).

A number plate can be deemed illegal if it fails to comply with certain standards.

Number plates must use a specific typeface known as the Charles Wright 2001 font. Any modifications to the font style, thickness, or size can render the plate illegal.

The spacing between letters and numbers must be consistent with DVLA guidelines. Altering the spacing to make the plate spell a word or name is illegal.

Plates must also have the correct size and layout, which is different for cars, motorcycles, and other vehicles.

The plates also need to be rectangular and correctly positioned on the vehicle. Custom shapes and arrangements can make a plate illegal.

They must be reflective and have a white background for the front plate and a yellow background for the rear plate. Tinted plates or plates with backgrounds other than the specified colours are illegal.

Legally manufactured number plates should display a British Standard. This ensures the plate meets durability, visibility, and reflectivity requirements – and has been approved by the DVLA.

Drivers can only display approved flags and identifiers on their number plates, including the Union Jack, Cross of St. George, Scottish Saltire, or Welsh Dragon. Other emblems and flags cannot be used.

Illegal plates can result in fines, MOT failure, and the police can remove a car from the road until the plates are corrected.

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Regarding DVLA approved rules for number plates, they must adhere to these rules.

The characters on a number plate need to be a certain display, height, and size:

• characters must be 79mm tall
• characters (except the number 1 or letter I) must be 50mm wide
• the character stroke (the thickness of the black print) must be 14mm
• the space between characters must be 11mm
• the space between the age identifier and the random letters must be 33mm
• the margins at the top, bottom and side of the plate must be 11mm
• vertical space between the age identifier and the random letters must be 19mm
• plate must be made of reflective material
• numbers must not be reflective
• white background (front plate)
• yellow background (back plate)
• display British Standard Number

These regulations apply for vehicles fitted after September 1st 2001.

From December 8th 2020 eligible zero emission vehicles (ZEVs) must display a green flag on the left hand side of the number plate.

It is possible to have 3D or 4D number plates – just as long as they confirm to all the other rules.

There are a few things that will make a number plate illegal.

Aside from having non-compliant font, spacing, size or design, there are other reasons why the police might stop and fine a driver.

This can include offensive or inappropriate language, use of symbols, or have an illuminated plate.

It is also illegal to rearrange the numbers and letters yourself or tamper with it in any way.

Yes, it is illegal to drive with a dirty or obstructed number plates on the roads in the UK.

This is because number plates must always be readable and visible to both police and automated systems, such as ANPR (Automatic Number Plate Recognition) cameras. 

If a plate is obscured by dirt, mud, snow, or anything else that makes it difficult to read, it does not comply with the law.

However, in cases where it appears that the plate has been deliberately obscured to avoid detection, then penalties may be more severe, potentially leading to prosecution by the police.

To avoid fines and penalties, it's important to regularly clean your vehicle’s number plates, especially after driving in adverse weather conditions like rain or snow, or if you’ve driven through mud or dirt. This is an essential part of winter car maintenance.

Driving with an obscured plate can result in a fine of up to £1,000, and your car may fail its MOT if the plate cannot be read clearly.

In more serious examples, or where the driver is a repeat offender, it could lead to further penalties.