What do number plates mean? What is legal?

What do number plates mean? What is legal?


What is in a Number Plate? Quite a lot, actually, they can give information about the age of a car, the area it's from, and since 2020, its fuel type. We explore what the standard UK number plate format means as well as what makes a personalised number plate legal or illegal, and what green number plates mean. 

With modern car design becoming even more outlandish, there's only one design feature that stays constant: the Number Plate. 

The UK number plate format 

It has changed a few times over the years, but the current style, in place since 2001, is broken down as follows.


Area code

The first two letters are used to identify the area the car was first registered. The first letter denotes the region, typically in a mnemonic style e.g. E = Essex, but not always. 

The second letter is allocated randomly to registration offices within that area. If you’re interested the chart can be found here. 

How to calculate a car's age from its number plate 

New number plates are issued twice yearly, the second number indicates the year, and the first number indicates in what half of the year the reg was issued. The numbers used as the year refer to the unit of year e.g. BD51 = 2001, but this becomes less straightforward as the years go on, a detailed breakdown can be found here.

The first two numbers denote the age of the registration number, but not necessarily the car. So although in most cases, you can tell how old a car is from its number plate, it is not always a sure thing.   

Older number plates 

Prior to 2001, the number plates followed a ‘Prefix’ style, the characters followed the format of one letter, three numbers, then three letters. 

In the Prefix format, the age is denoted by the first letter, ranging from A (1983) to X (2000), with only one new registration released each year. 

In a similar way to the modern format, the first two letters of the last group give the area the registration was first made. 

Green number plates explained 

Since December 2020, there has been an extra identifier allowed on number plates, the green Electric Vehicle plaque. Green number plates are only allowed on full EVs, and their purpose is to make spotting cars wrongly parked in EV-only spots easier.  

It also identifies the vehicle quickly for zero congestion or ULEZ charges.

Personalised number plates 

Sometimes known as ‘Cherished Plates’, these allow people to personalise their car by including their initials, age or other personal touches in their car’s number plate. 

Where can I buy a personalised number plate? 

There are a few ways to buy personalised plates, the best place to start is the DVLA plate auction, but there are quite a few other private websites where you can search for certain sets of characters.  

Prices start at around £200 and can soar into the millions.  

Can I keep my own number plate? 

Many ‘personalised’ plates are just normal format number plates with special meanings, if your number plate happens to contain your initials, or means something to you, you can remove the number from the car to put it on another.  

There are a few requirements for this, including how old the car is, and how long it has been on the road, but they are all laid out here.

Are personalised plates legal? 

Yes, but you have to follow the same rules for spacing and format as other plates.  

One very important rule is that you cannot make a car appear newer than it actually is by fitting a more modern registration plate. 

Number plate legality 

Because number plates are used for identification, they need to be easy to read by both humans and ANPR systems. 

Letter size and spacing 

The standard car number plate needs to have characters that are 79mm tall, and 50mm wide, the spacing between letters should be at a minimum of 14mm.  

One trend that these requirements aim to curtail is that of placing letters close to one another to create a different spelling, doing this can and is likely to incur a £1,000 fine and 3 points. 

There are also strict requirements on letter font and colour, no deviation from the standards set out by the DVLA is allowed. 

What flag can I have on my number plate? 

In 2009 the rules changed for national identity flags on number plates, cars registered in the UK can display a flag of England, Scotland, or Wales or the Union Flag.  

Abbreviations of the country names are also allowed but only under a specific guideline, such as “GB”, “Sco” etc, the full list is found here.

The European flag surrounding the “GB” wording is also still permitted, crucially it removes the need to display a separate “GB” sticker on your car should you travel to Europe.

Are number plate borders legal? 

You may have noticed some number plates have a coloured border around them, this was technically illegal before 2020. After 2020, new legislation has made number plate borders legal as long as they follow specific criteria: 

  • They are permanent 
  • They are non-reflective 
  • They are one shade with no fading or patterns 
  • Their letter size follows the specification 

What are Q plates? 

Q plates are used on vehicles that have either a classified or unknown history, they present no information regarding age or location. 

They are often seen on kit-cars, agricultural vehicles and imported cars. In these instances a Q plate may be used as the vehicle's exact manufacture date is not known, or they do not have a Vehicle Identification Number. 

Other vehicles often fitted with Q plates are ex-military vehicles that cannot have their history released. 

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