Look along the bottom edge of your number plate and you will see either BS AU 145d or BS AU 145e. Plenty of drivers see the older marking and assume they are now driving illegally. In most cases they are not. Here is the clear position.
The quick answer
If your plates were supplied and fitted on or before 31 August 2021 and carry the BS AU 145d marking, they remain legal on your vehicle. You do not need to replace them just because the standard has moved on.
If you are buying plates today, they must meet BS AU 145e. Any new plate manufactured and fitted from 1 September 2021 onwards has to comply with the newer standard.
What changed between the two standards
BS AU 145e is an enhanced version of BS AU 145d rather than a complete rewrite. Because it is stricter, a plate that meets 145e automatically satisfies 145d as well. The main areas where it tightened up:
- Tougher physical testing. Plates now face a fuller set of tests before a batch is approved, covering impact from stone chips and minor knocks, bending, abrasion, weathering and temperature extremes.
- Material resilience. The standard pushes for a harder, more durable plate that stays legible for longer.
- Character security. The standard states that the registration characters must not be removable, which raised questions at the time about raised and applied characters.
- Single solid black characters. This is the change most drivers actually notice, because it ended the two tone shadow effect fonts that were popular before 2021.
What it meant for 3D and 4D plates
When 145e arrived there was real uncertainty about whether raised characters would survive the "not removable" wording. The position that settled is that solid black acrylic or gel characters affixed to the plate face are currently viewed by the DVLA as legal under BS AU 145e, while characters containing clear or coloured sections are not.
So the practical effect was not a ban on 3D and 4D plates. It was a ban on coloured, translucent and two tone characters. Our guide to 3D and 4D plate legality goes deeper.
When you must fit plates to the new standard
You need BS AU 145e plates in any of these situations:
- You are replacing damaged, faded or cracked plates.
- You are fitting a private registration for the first time, or removing one and returning to the original mark.
- You are registering a new or imported vehicle.
- You want to upgrade the style of your plates.
- Your existing plates no longer carry legible markings.
In other words, the moment a plate leaves your car for any reason, its replacement must be 145e.
How to tell which standard your plates meet
The marking sits at the bottom right of the plate, alongside the manufacturer name or trademark. If you cannot find any British Standard marking at all, the plate is not compliant with either standard and should be replaced, since the marking is itself a legal requirement.
Bear in mind that a plate showing BS AU 145d can only rely on its legacy status if it genuinely was fitted before September 2021. Fitting an old stock 145d plate today would not be compliant.
Should you upgrade anyway?
There is no legal obligation, but there are two good reasons to consider it. The first is condition. Plates fitted before September 2021 are now several years old, and British weather, road salt and jet washing take a toll. Yellowing, crazing and delamination all cause MOT problems.
The second is legibility. If a plate has faded, the contrast that cameras rely on drops, and an illegible plate is an offence in its own right regardless of which standard it was made to.
Frequently asked questions
Will a BS AU 145d plate fail an MOT?
Not because of the standard alone, if it was legitimately fitted before September 2021 and is in good condition. It will fail if it is illegible, damaged, incorrectly spaced or missing required markings.
Can I keep a 145d plate on the front and fit a 145e on the rear?
Legally the older front plate can stay if it was fitted in time, but the pair will not match visually. Most people replace both together.
Is there a BS AU 145f coming?
Standards are reviewed periodically, but 145e is the current requirement. We update this article whenever the position changes.
Does this apply in Northern Ireland?
Plates in Northern Ireland must meet an approved British Standard in the same way, although registration formats differ. Check the guidance on nidirect for local detail.
Replacing your plates
Every plate we manufacture meets BS AU 145e, with permanent markings and solid black characters. Choose standard plates for a straight replacement, or upgrade to 3D gel or 4D while you are at it.