If you have shopped for number plates online, you have almost certainly seen the phrase "BS AU 145e certified" in a product description. Most sellers never explain what it means. This guide does, in plain English, so you know exactly what you are paying for and how to check that the plates on your car are legal.
What BS AU 145e is
BS AU 145e is the British Standard for retroreflective number plates. It is the current version of a standard that has existed since the 1960s, and the letter "e" simply marks the latest revision. It became mandatory on 1 September 2021, which means every plate manufactured and fitted in the UK from that date onwards must meet it.
The standard exists for two reasons. The first is readability. Automatic number plate recognition cameras need to read your registration reliably in rain, fog, darkness and glare. The second is durability. A plate that cracks, fades or peels within a year is a safety problem as well as an annoyance.
What the standard actually covers
BS AU 145e sets rules across several areas at once:
- Materials. Plates must be made from an approved reflective sheeting and an acrylic face that passes a series of laboratory tests.
- Durability testing. Plates are subjected to impact, bending, abrasion, weathering and temperature cycling tests before a batch is approved.
- Reflectivity. The background must reflect light to a measured minimum level. The characters themselves must not be reflective.
- Font. Only the Charles Wright 2001 typeface is permitted, at prescribed character heights, widths, stroke widths and spacing.
- Colour. Characters must be a single solid shade of black. Front plates use a white background, rear plates use yellow.
- Character security. The registration characters must not be removable.
- Markings. Each plate must carry specific permanent information, explained below.
The markings on the bottom of your plate
Flip any road legal UK plate over, or look along the lower edge, and you will find four pieces of information. They are not decoration. They are a legal requirement.
- The British Standard number, shown as BS AU 145e, positioned at the bottom right.
- The manufacturer name or trademark, also at the bottom right.
- The supplying outlet name and postcode, positioned at the bottom centre.
All of this must sit below the registration mark, with a gap of at least 7mm between the bottom of the registration characters and the markings. If a plate arrives without these details, it is not road legal, no matter how good it looks.
Does BS AU 145e ban 3D and 4D plates?
No, and this is where a lot of online advice gets it wrong. Raised characters are not banned. What the standard requires is that characters are a single solid shade of black and are not removable. Solid black acrylic and solid black gel characters are currently viewed by the DVLA as acceptable under BS AU 145e.
What the standard does rule out is anything that breaks the solid black requirement. That includes printed fonts using two tones of grey to fake a shadow effect, and raised characters containing clear or coloured sections, sometimes sold as "Krystal" or "Neon" plates. Those are not legal for road use.
If you want the raised look while staying inside the rules, our 4D number plates and 3D gel number plates are made to BS AU 145e with solid black characters. You can read more in our guide to whether 3D and 4D plates are legal in the UK.
What happens if your plates do not comply
Non compliant plates can cost you an on the spot fine of up to £1,000. They will also fail an MOT, because the tester checks that the registration is correctly displayed and legible. In more serious cases, a registration can be withdrawn entirely.
How to check your own plates in thirty seconds
- Look for the BS AU 145e marking. If the plate was fitted after 1 September 2021 and the marking is missing, it is not compliant.
- Check the supplier name and postcode are present and readable.
- Look at the characters in daylight. They should be one flat shade of black with no grey shading, tint or colour.
- Check the front plate is white and the rear plate is yellow, with no background pattern.
- Run a fingernail along a character. It should be firmly bonded, not lifting.
Frequently asked questions
Is BS AU 145e the same as being DVLA approved?
Not quite. BS AU 145e describes the plate itself. Separately, only a Registered Number Plate Supplier is legally permitted to manufacture road legal plates. You need both: a compliant plate from a registered supplier.
Do I need to replace plates that say BS AU 145d?
No, provided they were fitted on or before 31 August 2021. Plates made to the earlier standard remain legal on the vehicle. Any replacement you buy now must meet 145e.
Does BS AU 145e apply to motorcycles?
Yes. Motorcycle plates must meet the same standard, although they use a smaller prescribed character size and are only required at the rear.
Can I make my own plates at home?
Not for road use. Plates for public roads must come from a Registered Number Plate Supplier who has verified your identity and your entitlement to the registration.
Buying with confidence
Every plate we manufacture is made to BS AU 145e with solid black characters and the required permanent markings. Browse our standard number plates, 3D gel plates and 4D plates, or get in touch if you are unsure which option suits your vehicle.