Motorcycle number plate rules in the UK: what the law actually says
Motorcycle plates follow a different set of rules to car plates, and the differences catch people out. If you have just bought a bike, replaced a damaged plate or are planning a personalised registration, this is what the law requires.
Your bike needs a rear plate only
Motorcycles and motor tricycles registered on or after 1 September 2001 must only display a number plate at the rear of the vehicle. There is no requirement for a front plate, and fitting one is not standard practice.
If your bike was registered before 1 September 2001 you may also display a plate at the front, but you do not have to.
The characters must be on two lines
This is the rule that surprises most riders. Motorcycle and motor tricycle plates for bikes registered on or after 1 January 1973 must have the registration set out on two lines. A single-line bike plate is not road legal, however tidy it looks.
In practice that means the age identifier goes on the top line and the random letters on the bottom, which is why a bike plate is close to square rather than the long oblong you see on a car.
The measurements
For motorcycles and tricycles registered on or after 1 September 2001, the characters must be:
- 64mm tall
- 44mm wide, except the number 1 and the letter I
- 10mm character stroke, meaning the thickness of the black print
- 10mm space between characters
- 30mm space between the age identifier and the random letters
- 13mm vertical space between the two lines
- at least 11mm margin at the top, bottom and sides
Those are smaller than the equivalent car figures, which is why a car plate scaled down is not the same thing as a bike plate.
The British Standard
Any plate fitted from 1 September 2021 must be marked BS AU 145e. Plates fitted before that date carry BS AU 145d and remain legal, so you do not need to replace a compliant older plate just because the standard has moved on.
A plate must also be permanently and legibly marked with the British Standard number, the name or trademark of the manufacturer or supplier, and the name and postcode of the supplying outlet. If a plate has no supplier markings at all, it is not a road-legal plate.
Colour and material
Vehicles manufactured after 1 January 1973 must display plates made of reflective material, with black characters. The rear plate has a yellow background. Since a bike only needs a rear plate, a road-legal motorcycle plate is a yellow one.
Flags and identifiers
You may display one of the Union flag, the Cross of St George, the Cross of St Andrew or the red dragon of Wales on the left-hand side of the plate, with identifying letters such as GB, UK, ENGLAND, SCOTLAND, CYMRU or WALES. The flag or letters cannot sit on the margin and cannot be more than 50mm wide.
What it costs to get it wrong
You cannot rearrange or misrepresent the characters, and that includes using fixing bolts to alter the appearance of a letter or number. Doing so risks a fine of up to £1,000, an MOT failure, and in some cases permanent withdrawal of the registration number.
Worth remembering that a show plate is not a road-legal plate. Show plates carry no legal markings and are for off-road and display use only.
Figures in this article come from DVLA leaflet INF104 and gov.uk. If you are unsure what your bike needs, our team can talk it through before you order.