Diesel filters can easily break – stop start urban driving contributes to this as the filters require prolonged high heat to work properly.
Some drivers opt to remove them – as this is a legal procedure, which cost a few hundred pounds instead of filter repair which can cost £1,000.
However driving a vehicle with the filter removed could lead to £1,000 fine for a diesel car or even £2,500 for a diesel van.
DVSA says it has found 1800 vehicles on the road without the required filters.
It is possible to make it look like the filter is intact but by cutting into it, removing the inner filter and then welding it shut again. This is currently enough to pass an MOT which only requires visual inspection of the DPF.
The DVSA is planning new tests from May 2018 to detect tampered filters.
DVSA Chief Executive Gareth Llewellyn has said “DVSA continues to pursue such offences and will take action against any MOT garages found to be conducting illegal modifications.”