Car Number Plates Explained: A guide to understanding vehicle registration

Thursday 4th September 2025

No matter what car you drive, every vehicle has one thing in common: a number plate. But what do all those numbers and letters mean? And what happens if you want something a little more personal? In this guide, we’ll explain everything you need to know about licence plates.

How do standard number plates work?

Twice a year, the DVLA (Driver and Vehicle Licensing Agency) releases new registration plates. These consist of a combination of numbers and letters.

Region

The first two letters indicates the region it was registered. For example:

• L represents London
• B represents Birmingham
• M represents Manchester

The second letter narrows it down further to the specific DVLA office within that region.

Age post-2001

After 2001, a new system came into play. If the vehicle was registered between 1st March and 31st August, the plates will show the last two digits of the year, e.g. 2025 will be 25. If registered between September 1st and before 1st March the following year, the number 50 will be added to the year, e.g., 25 will become 75.

Age before 2001

For vehicles registered prior to 2001, the year is represented by a letter in the alphabet, starting with A in 1983, skipping letters which could be confused with numbers or similar letters, such as O and Q, and ending in Y in 2001.

Age before 1983

Going even further back, the letter that represents the year changes position. Between 1983 and 2001, the letter appears as a suffix, whereas before 1983, it appears as a prefix.

Random letters  

The last three letters are randomly generated and don’t have any significant meaning.

How do personalised number plates work?

Personalised number plates are a way of making your car   personal to you. They’re perfectly legal when purchased through the DVLA, a private broker or in a private sale.

You can search through a list of number plates that include your desired numbers or letters for sale on the DVLA website. If a car is already registered with the number plate you want, you could contact the owner privately or through a broker (although this is likely to be much more expensive).

Already have a private plate? You can transfer it to your next car for a fee through the DVLA website.

Legal mods and features

While obscuring the details on your number plate is illegal, you can modify your number plate as long as it adheres to British Standards (BS AU 145e). This can include the following changes:

• Green flash for electric vehicles
• UK identifier
• 3D/4D gel text (as long as it complies with the DVLA’s standards)

Banned or illegal number plates

The DVLA bans plates that are rude or offensive, including offensive language that’s misspelt or spelt phonetically. As a general rule of thumb, it’s best to avoid numbers or letters that refer to the following:

• Politics
• Religion
• Sex
• Illegal activity
• Vulgar language

Other illegal modifications include:

• Changes to the number plate font, such as the font thickness and size.
• Changes to the space between the letters and numbers on your number plate.
• Changing the background colour or image of the number plate. The characters need to be black on a white background on the front plate and white on a yellow background on the back plate.
• Adding logos to your number plate.
• Changes to the size of your number plate.

It’s also illegal to make changes to your number plate that attempt to obscure the number and avoid detection from speed cameras. This could include:

• Adding tape or screw covers to change the lettering
• Reflective coating
• 3D or 4D lettering that can obscure the readability of the plate
• False number plates

Modifying, or ‘modding’, your number plate can be more hassle than it’s worth, so we recommend sticking with the plate issued by the DVLA.

What happens if you’re caught with an illegal plate?

Driving with an illegal plate can lead to serious consequences. If you choose a plate that is later banned for being offensive, you’ll be left out of pocket for the cost of the plate and unable to drive until a new number plate is issued.

If you are caught by the police for illegal modifications, you could be fined up to £1,000. A clear, legible number plate is one of the specifications required to pass your MOT, so illegal modifications could result in MOT failure.

Due an MOT? Book your next MOT in just a few clicks at your nearest Formula One Autocentres branch. Don’t forget to check out common reasons why your car might fail its MOT in our guide.