Driving around with legal number plates should be a straightforward business. Yet it’s surprisingly ambiguous. While most drivers are happy to use the plate supplied on their brand-new car, some motorists like to stand out from the crowd with personalised plates and custom designs. The Driver and Vehicle Standards Agency (DVSA) set out criteria, which if not followed, can result in penalties.
On this page we cover legal number plate spacing, specifications and fonts, and even what those new green plates mean. We’ll also detail the consequences and fines involved if you get it wrong. Getting it wrong can mean using an illegal plate, but also not cleaning your car sufficiently.
With road policing units seizing non-compliant number plates nationwide, and the government bringing in greater use of Automatic Number Plate Recognition (ANPR) to fine drivers for misdemeanour offences, it might be worth your while to brush up on what is and is not permitted when it comes to car registration plates.
What does a legal number plate look like?
How should country identifiers be displayed?
What about 3D and 4D number plate?
What about number plate lights?
What does a legal number plate look like?
Random fact for a pub quiz question: in the same way the King owns all the swans of the UK, the Secretary of State owns all the number plates.
Anyway, registration plates for cars are split into three groups; those before 1 January 1973, those before 1 September 2001 and those from 1 September 2001.
Legal registration plates, since the system was changed in September 2001, are comprised of three elements:
A: The first two letters, which indicate the county/country of origin
B: The two numbers, which indicate the year the vehicle was first registered
C: Three random letters, after a 33mm gap, serving to provide unique combinations
A lot of the confusion around number plate legality comes from the fact the rules have changed periodically and so certain cars, due to their age, can ‘get away’ with not complying with today’s standards all new plates need to meet. For example, before Septmber 2001, the ‘A’ element of the registration plate was a single letter, rather than two.
Furthermore, since January 2021 number plates must conform to British standard, BS AU 145e, which sets the requirements out like the table below.
| Number plate legal details | Present (post-Sept 01) |
Group 1 (pre-Sept 01) |
Group 2 (pre-Jan 73) |
Motorcycles, Tricycles |
| Character height | 79mm | 89mm | 79mm | 64mm |
| Character width (Number ‘1’ or Letter ‘I’ excluded) | 50mm | 64mm | 57mm | 44mm |
| Character stroke | 14mm | 16mm | 14mm | 10mm |
| Space between characters | 11mm | 13mm | 11mm | 30mm |
| Space between age identifier & numbers i.e. gap | 33mm | 38mm | 33mm | 30mm |
| Top, bottom & side margins minimum | 11mm | 13mm | 11mm | 11mm |
| Vertical space in gap (if across 2 lines) | 19mm | 19mm | 19mm | 13mm |
The plates are also required to show the name or trademark of the plate manufacturer and the name and postcode of the supplier, since all suppliers have to be officially recognised. These are measures to help stamp out illegal suppliers and protect consumers from the identity theft.
Front registration plates need to be white with black lettering and rear plates yellow with black lettering. Of course, cars pre-dating the yellow and white regulation tend to be classics, where silver or white lettering sit on a black background.
The font dates back to 1935, when Charles Wright created number plates for vehicles. His font is generally the accepted standard, though confusingly it has no official typeface name. Over the years there have been updates on the unofficially named Charles Wright font. Charles Wright New and more recently Mandatory make an appearance in the DVSA’s official guide to number plate legality. The subtle differences are most noticeable in the letters ‘M’ and ‘W’, where the evolution is aiming to ensure these letters can be clearly seen by ANPR. Any other font or styling, such as italics, is not permitted.
How should country identifiers be displayed?
There are specifications for how and where country flags, country abbrevations and those green stripes (denoting electric vehicles) should be.
Each of the kingdoms of the UK can display their own flags, and/or you can display CYM, ENG, GB, SCO or UK as accepted identifiers. They can be margin stickers, sitting on top of the plate, or integrated as part of the printed design, but outside of these stringent rules, no other identifiers are acceptable.
Most countries will accept the GB integrated into the plate, negating the need for an extra GB bumper sticker, but Cyprus, Malta and Spain want you to have both. It’s worth noting however that as the UK embraces the changes brought around by Brexit, there is a requirement to display a ‘UK’ bumper sticker and hide or remove the GB one, if driving on the continent.
What’s not allowed then?
Visibility and reflectivity are key to your registration plate doing its job – which is to say making you and your car identifiable. Thus anything that impinges on the legibility of the number plate is likely to raise a red flag to law enforcement.
This can include, but is not limited to, moving the screws to alter the appearance of the letters, displaying a different font in a different size and not complying with the relevant spacing, as above, having the plate information across three lines instead of one, or two (for vans, motorbikes, etc.) and messing about the colours or lights.
For reasons only known to them – we suspect to avoid being picked up by speed cameras – some drivers have attempted to make all the black letters different shades of black. It won’t surprise you to learn that the rules explicitly state ‘all one shade of black’.
What about a dirty number plate?
Yes, since running around with dirty number plates makes it harder to read your plate, you can actually be stopped and fined if muck is obscuring your plate. Granted, the winter weather can make cleaning the car seem a futile effort (but can easily be overcome with a good pre-wash).
In addition to the mild inconveniences of catching your clothing on the dirt in a tight parking spot, and getting a cheeky message from a stranger written into the muck, the fine can be a grumpy £100 on-the-spot fixed penalty, or up to £1,000 once the police manage to catch up with you. Ouch.
A dirty plate can also make you more likely to be a victim of crime, so keeping your car clean with the best car shampoos or even basic waterless wash (no excuses!) has multiple advantages. 
What about 3D and 4D number plates?
3D and 4D number plates can in fact be legal, although many drivers believe they’re not. However, due to the way in which they’re created, i.e. the letters and numbers are raised, 4D plates can cause problems. In brief, if the raised letters inhibits reading the plate clearly, they’re not compliant.
They’re also a bit of a pain to keep clean too, so they’re best avoided unless you’re Detailer Extraordinaire when you clean the car.
What about number plate lights?
Even if you haven’t been especially observant, you might have been almost blinded by the glare of number plate lights on some vehicles. These new-age LED lamps are better suited to cars than the old bulbs as they’re more stable and more energy-efficient, but we have been noticing the brightness creeping up so much as to actually obscure the plate too.
There’s currently no legal requirement around how dim or bright number plate illumination should be. The only stipulation is that the lights should be white and no other colour to mitigate problems with reading the plate accurately. If your lights are so bright, they create glare for other drivers—or, as the driver possibly intended, ensure the plate can’t be read by cameras, you may attract the attention of traffic police.
What penalties can you face for having an illegal plate?
By far the most unwanted penalty for having an illegal plate is the seizure of your whole car. It might sound disproportionate, but the police are required to seize any evidence of an offence committed, which will best demonstrate how the offence has been committed in court. If the likelihood of conviction is higher by seizing the car, the police have the authority to do so. This can get pretty expensive, since there is a ‘release fee’ of £200, plus a storage fee of £20 per day.
In most instances, provided you’re not a repeat offender, the police will take pictures of the illegal plate and write it up as a ‘vehicle defect’, giving the driver a form called a ‘vehicle defect rectification notice’. The driver then has 14 days to correct the issue through the proper channels, which will stamp the form to confirm the work has been done. The form is then presented, within the 14-day period, at a local police station and the matter is closed.
As we mentioned above, an illegal, damaged or or dirty plate could cause your car to fail its annual MOT, meaning you’ll be forced to change it at some stage.
Legitimate registration plates are often cloned by repeat offenders, out to commit crimes in your name. Innocent parties regularly end up with a miserable heap of life admin, trying to extricate themselves from the fraudulent use of their number plates. Perpetually having dirty plates could make you more suspectible to identity fraud too, since you may find it difficult to prove you were elsewhere in the country when a crime was being committed with your plates.
If you’re in doubt, your nearest certified suppliers can be found on this gov.uk webpage and keep your registration plates clean.
