BS AU 145e explained
BS AU 145e is the British Standard that road-legal number plates must meet. Introduced in September 2021, it replaced the older 145d standard and tightened the rules on how plate characters can be displayed.
If you have shopped for plates recently you will have seen "BS AU 145e" mentioned. It is the British Standard that sets out how retroreflective number plates must perform and be marked. Every road-legal plate we make meets it — here is what it actually means.
What is BS AU 145e?
BS AU 145e is the British Standard for retroreflective number plates. It defines the performance requirements a plate must meet — including its reflectivity, durability and how it is constructed — so that registrations remain clearly readable, including at night when light is reflected back from headlights. A plate manufactured to this standard carries the relevant markings showing it complies.
When did it come into force?
BS AU 145e came into force on 1 September 2021 and replaced the previous standard, BS AU 145d. From that date, new plates fitted to vehicles used on public roads in the UK are expected to be manufactured to BS AU 145e. Plates already correctly fitted before the change do not need to be swapped simply because the standard updated, but any new plates should meet the current standard.
The key change: single solid black characters
One of the most noticeable points under BS AU 145e is that characters must be a single, solid black colour. This rules out two-tone or shaded character effects on road plates. Some styled finishes that use shading, a "ghost" outline, or coloured highlights to make characters appear two-tone are therefore not road legal under this standard.
Importantly, this does not ban raised finishes. A 3D gel or 4D plate can still be road legal, because the characters are raised but remain a single solid black colour. It is the use of multiple colours or shaded effects within the characters — not the depth — that crosses the line.
What a road-legal plate must show
- Characters in a single solid black colour — no shading or two-tone effects.
- A reflective background — white at the front, yellow at the rear.
- The mandatory font with the correct character sizes and spacing.
- Manufacture to BS AU 145e, with the required supplier and standard markings.
What it means when you order
When you build your plate and choose a road-legal option, we make it to BS AU 145e with solid black characters and the correct markings. If you want a styled or shaded effect that isn't road legal, that can only be supplied as a show plate for off-road use — see our road-legal number plates page for the full picture.
Common questions
Do I have to replace plates made to the old 145d standard?
Plates correctly fitted before 1 September 2021 don't have to be replaced just because the standard updated. New plates you buy now should be made to BS AU 145e.
Are 4D and 3D gel plates allowed under BS AU 145e?
Yes, provided the characters are a single solid black colour and the plate meets the font, spacing and reflectivity requirements. The raised effect itself is fine; shaded or coloured characters are not.
How do I know a plate meets the standard?
A compliant plate carries the supplier name, postcode and the British Standard marking. All our road-legal plates are made to BS AU 145e.
Build a BS AU 145e plate
Design a road-legal plate made to the current British Standard, with solid black characters and free UK delivery.