BBC Transport Correspondent Christopher Wain reports

Many drivers alter the spacing and typefaces on number plates to spell names and messages. But some plates can make registration numbers unreadable by speed cameras.

It is already an offence to make letters look like numbers and vice versa, but the Driver Vehicle Licensing Agency (DVLA) in Swansea has said it intends to crack down.

Personalised number plates are popular and legal

Thousands of personalised registration numbers are allowed - the DVLA sells assignment rights to attractive numbers and many people are prepared to pay high sums for novelty numbers.

Footballer-turned-film star Vinnie Jones, for example, has a number plate featuring his initials.

But the problem is when people change the letter spacing and make the plate hard to read. Cars with these plates fail MOT tests and there is a maximum �1,000 fine.

Police concerns

A simple change in letter spacing can make 13 look like B or 8. The letter O can look like D, 12 can look like 15 and the letter S can get confused with the number 5.

Police are concerned that vehicles involved in hit and run accidents can be difficult to trace.

The DVLA plans to work with the Association of Chief Police Officers (ACPO) to crackdown on drivers. From 1 March people without correctly displayed plates may have their registration marks withdrawn permanently without compensation.

John Owen, deputy chief constable of North Wales Police and a member of the ACPO committee, said: "Some order needs to be returned to the manner in which some people display their vehicle numbers.

"These are not offences that people commit by accident, these are deliberate."