Thousands of UK drivers are illegally driving modified cars without diesel exhaust filters, an investigation has found.

Due to processing large amounts of particulate matter from diesel exhaust the filters can easily become clogged and likely to break.

To replace the broken filter can cost up to £1000, so to avoid the cost some drivers have opted to have the filter removed.

The procedure to remove the filter is legal and costs only a few hundred pounds, but driving the modified vehicle is illegal and any vehicle found with a modified filter will be subject to a fine of £1,000 for a car or £2,500 for a van.

Eighteen hundred diesel cars in the UK have been found by The Driver Vehicle Standards Agency to be on the road without the legally required diesel particulate filters.

The pollution produced by the particulate matter in the diesel fumes can be damaging to the heart and lungs as well as unborn children in the womb. Noxious fumes created by diesel engines have been linked by The World Health Organisation to 38,000 premature deaths every year.