Motor Vehicle Expert
MOT legal guide

Can Number Plate Fail MOT?

Yes, a number plate can fail an MOT in the UK if it is missing, damaged, dirty, insecure, incorrectly spaced, difficult to read, has the wrong colour background, uses an illegal font or has a faulty number plate light.

Quick answer Pre-MOT checks

Quick answer

A number plate can fail an MOT if it cannot be read clearly, is badly damaged, is insecure, has incorrect colour or layout, or does not meet legal display requirements.

A simple clean, replacement bulb or new number plate can often fix the issue before the test.

Common reasons number plates fail MOT

Dirty or obscured plate

Mud, grime, covers or damage can make the plate hard to read.

Cracked or damaged plate

Cracks, delamination or missing sections can cause failure.

Incorrect spacing

Personalised plates with altered spacing can fail.

Illegal font

Stylised letters, unusual fonts or altered characters can be a problem.

Wrong colour

Front plates should be white and rear plates yellow.

Insecure fitting

Loose plates or poor mounting can fail if not secure.

Spacing, font and personalised plates

Personalised number plates are common MOT problem areas when letters or numbers are moved to make a word or name. Even if the plate looks readable to you, it can still fail if spacing, font or layout is not legal.

  • !Do not move letters or numbers closer together.
  • !Do not use decorative screws to change how characters look.
  • !Do not use novelty fonts or stylised characters.
  • !Do not use tinted covers that make the plate harder to read.

Can number plate lights fail MOT?

Yes. Rear number plate lights must illuminate the registration plate clearly. If the bulb is out, the lamp is damaged, wiring has failed or the plate cannot be read at night, it can cause MOT problems.

Easy check

Turn lights on and check the rear plate is lit evenly.

Common fix

Replacing a small bulb is often cheap and quick.

Pre-MOT number plate checks

  • 1Clean both front and rear plates.
  • 2Check for cracks, peeling, delamination or missing sections.
  • 3Make sure plates are firmly attached.
  • 4Check spacing and font are standard and legal.
  • 5Turn lights on and check the rear number plate lamps work.
  • 6Replace damaged or illegal plates before the test.

Should you replace a damaged number plate before MOT?

If the plate is cracked, peeling, unreadable, badly faded or incorrectly spaced, replacing it before the MOT is usually the simplest option.

Number plates are normally cheaper to fix than many MOT failures, so they are worth checking early.

Frequently asked questions

Can a dirty number plate fail MOT?

Yes, if it cannot be read clearly.

Can a cracked number plate fail MOT?

Yes, especially if characters are affected or the plate is hard to read.

Can private plates fail MOT?

Yes, if spacing, font or layout is not legal.

Can number plate lights fail MOT?

Yes, if the rear registration plate is not properly illuminated.

Can tinted number plate covers fail MOT?

They can, especially if they make the plate harder to read.

Should I replace plates before MOT?

Yes, if they are damaged, illegal, faded or hard to read.