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Motorbikes and the law: Number plates and exhausts

Published: 26 July 2018

Updated: 26 July 2018

Welsh police have been clamping down on bikers with loud pipes and illegal number plates in an effort to decrease anti-social behaviour on the roads.

This got MCN thinking about what the law says on the subject and how it is generally applied, so we consulted Solicitor and Author of the MCN Law Column, Andrew Campbell, to find out. Here’s what he said:

Number plates

The rules dealing with number plates can be found in The Road Vehicles (Display of Registration Marks) Regulations 2001.

Motorcycles registered on or after September 1 2001 must only display a number plate at the rear of the vehicle. If you ride a motorbike registered before this date, then you can also display a number plate at the front, but you don’t have to.

Illegal plates can get you a £1000 fine

Motorcycle number plate numbers should be on 2 lines. A rear number plates should be made from a reflective material, display black characters on a yellow background (white background if using a front plate) and have no background pattern.

The characters can be 3D (two-tone) and the font used must be "Charles Wright" (this has been the case since 2001).

Minimum size

There is no rule governing the size of the plate, but there are rules about the size and layout of the text which obviously limits how small you can go. Post 2001, the characters must be 64mm tall and 44mm wide (except the number 1 or letter I).

The thickness of the 'stroke' of the letters must be 10mm and the space between letters must be 10mm. The space between the age identifier and the random letters must be 30mm, and the vertical space between the age identifier and the random numbers must be 13mm.

Finally, there must be 11mm between the characters and the edge of the plate.

If you apply these rules logically, it would be possible to have a legal plate with the registration 'A1 III' which was considerably smaller than one with the registration 'A888 WWW'. 

Displaying a flag

You can display one of the following flags with identifying letters on the left-hand side of the number plate:

  • Union Flag
  • Cross of St George (England)
  • Cross of St Andrew (Scotland)
  • Red Dragon (Wales)

The letters, or national identifiers, you can have are:

  • GREAT BRITAIN, Great Britain or GB
  • UNITED KINGDOM, United Kingdom or UK
  • CYMRU, Cymru, CYM or Cym
  • ENGLAND, England, ENG, Eng
  • SCOTLAND, Scotland, SCO or Sco
  • WALES or Wales

The flag must be above the identifier. You can’t have the flag or letters on the number plate margin, and neither can be more than 50 millimetres wide.

If you display the Euro symbol it must be a minimum height of 98mm, have a width between 40mm and 50mm, have a reflective, blue background with 12 reflecting yellow stars at the top and show the member state (GB) in reflecting white or yellow.

Bolt placement

Strategically placing bolts to form a different character or tweaking the spacing to spell out a message is illegal. Plates that are so dirty as to be illegible are also illegal.

The number plate must be legible and adhere to the rules so they're easy to read as they provide essential information about your vehicle to insurers, police and other drivers.

The punishment

Breaking the law in relation to number plates can lead to a significant fine (up to £1000), a failed MOT and the loss of the plate (if it is a personal plate you will not get back the money you paid for it).

The Driver and Vehicle Licensing Agency (DVLA) and traffic officers are cracking down on number plate offences so now is the time to check your plates conform.

The worst areas for number plate offences (2015-2017)

  1. Metropolitan (Greater London area)- 3058
  2. North Wales- 1381
  3. Norfolk- 1175
  4. Thames Valley- 855
  5. Hertfordshire- 838
  6. Greater Manchester- 754
  7. Hampshire- 735
  8. Cheshire- 733
  9. Suffolk- 682
  10. Avon and Somerset- 629



Loud exhausts

It is illegal to alter your pipes to make them louder

The rules dealing with loud exhausts can be found at Regulation 54 (2) The Road Vehicles (Construction & Use) Regulations 1986 which deals with silencer/ exhaust system altered to increase noise and Regulation 97 of The Road Vehicles (Construction & Use) Regulation 1986 which deals with the avoidance of excessive noise.

There are limits to the amount of noise that motorcycles can make on public roads.

It's illegal to modify the system to make a vehicle noisier

In relation to modified exhausts it’s illegal to modify the system to make a vehicle noisier after it has been ‘type approved’ (checked it meets environmental and safety standards).

The police can also take action if your vehicle’s silencer doesn’t work in the way it was designed or if you’re driving in a way that creates too much noise.

82-86 decibels is the current maximum permitted noise level for a motorcycle, the bracket depending on engine size. Most police forces use 90 decibels as the limit to take account for the effects of any wear and tear.

The penalties for breaking the law vary from a verbal warning to a non-endorsable fixed penalty notice for the offence of 'silencer/exhaust system altered to increase noise' (£50) to non-endorsable fixed penalty notice for the offence of 'avoidance of excessive noise' (£50).

This article was written by Andrew Campbell, a Solicitor at Bikelawyer Motorcycle Accident Solicitors.

Andrew is MCN Legal Expert and has authored the MCN Law column for more than 10 years.

Find your next two-wheeled companion at MCN Bikes for Sale.

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