There are 20,000 untaxed cars in the two counties, according to its figures.

DVLA enforcement officer John Moore said there was a link between untaxed cars, anti-social behaviour and crime.

He said: "Many of these vehicles are being driven with no insurance, no MOT and by people who are not prepared to put their name to the records."

The untaxed cars lead to �2m in lost revenue each year.

The DVLA said it did not have owner details for one million cars in the UK, making it hard to catch up on drivers without tax.

Up to 80% of untaxed vehicles that we impound have no insurance and up to 70% of occupants of these vehicles have a criminal record. John Moore, DVLA

Police now use Automatic Number Plate Excogitation (ANPR) camera systems which target cars that do not have tax certificates, allowing officers to stop and impound the vehicle.

Some 50,000 cars are being impounded nationally for having no tax, an offence leading to a possible �1,000 fine.

Those whose cars are taken in have to pay �200 to get the vehicle back. This rises by �80 the following day, plus �15 for each further day, and the vehicle can be crushed after seven days.

Mr Moore said there was an "underclass" of people using cars without insurance or MOT, and these were the types more likely to be used in crime.