There are almost six million part-worn tyres that don't meet minimum safety standards on UK roads, according to new research by LV= car insurance.
Since 2009, 23 million part-worn tyres have been sold in the UK but a quarter of these were illegal meaning 1.5 million motorists have bought sub-standard rubber.
UK law states all part-worn tyres must be stamped in order to show they have been checked in accordance with the legal requirements. Shockingly, only half (51 per cent) of British motorists were aware that these regulations existed when buying their second-hand tyres.
Since 2009, over half a million motorists have reported skidding at some point while they have driven on part-worn tyres, with 512,000 reporting noticeably longer braking distances.
With an average of £150 for a part-worn set, motorists can make a big saving by buying second-hand tyres.
The tough financial climate and ever-increasing cost of motoring means the part-worn tyre market is booming. However, some unscrupulous dealers are knowlingly selling illegal tyres and Trading Standards said the number of part-worn dealerships under investigation has almost doubled since 2009.
Tyres should be checked regularly with some imperfections being easy to see on visual inspection. Yet 78 per cent of motorists check their tyres less than once a month, with one in 20 leaving it up to a year when their MOT comes around, according to the research.
Tyres must have at least 1.6mm of tread over the central three-quarters of the width of the tread and around the entire circumference. If there is less tread than this, the tyre needs to be changed.
Driving with unsafe tyres is a criminal offence, with fines of £100 and three penalty points per offending tyre. According to recent police data, there's been a nine per cent increase over the past five years in drivers being pulled over for defective tyres.
Managing director of LV= car insurance, John O’ Roarke, said: “In the current economic climate, motorists are understandably looking to cut costs wherever they can and buying quality used tyres is one way to do this.
"Those wanting to buy part-worn should look for reputable dealers that work with the British Standards Institution, which ensures all tyres sold meet the minimum requirements."