Franchised car dealers should be working to highlight the risks of cheap alternative tyre suppliers after a Trading Standards investigation revealed that 139 of the 152 part-worn outlets were selling illegal and unsafe tyres to unsuspecting motorists.

Investigations by TyreSafe and Trading Standards have revealed the scale of the problem over the past five years and TyreSfe said that the trend suggested that part-worn retailers are either "ignoring their responsibilities when selling tyres or do not have the required skill to serve motorists properly".

During test purchases which formed part of the investigation, some retailers fitted tyres with water in them to customers' wheels, while others provided the wrong size of tyre and the supply of examples with nails and other objects embedded in them was also common. 

TyreSafe chairman, Stuart Jackson, said: “While the shocking findings of joint investigations may reveal some part worn dealers are compliant, even if it is fewer than one-in-ten, motorists have a 90% chance of visiting an outlet selling illegal tyres.

“As far as TyreSafe is aware, there is no other retail sector with such an atrocious track record.

"Let’s remember these dealers are selling safety critical components - when tyres are driven in an unroadworthy condition, a vehicle’s braking and steering are compromised, and road users are put at significant risk of a catastrophic tyre failure. 

“TyreSafe pledges to continue its potentially life-saving work with Trading Standards and partners with an ambition to drive compliance and competence among part worn retailers.”

A recent case has resulted in part worn retailer Hemel Tyres in Bury Road, Hemel Hempstead, being ordered to pay over £7,000 in fines and costs, following prosecution by Hertfordshire Trading Standards.

Terry Hone, executive member for Community Safety at Hertfordshire County Council, said: “We hope that this sends a message to the part-worn tyre market in Hertfordshire that we take these matters very seriously.

"Our consumers should be able to expect that any tyre they buy for road use complies with safety standards.” 

In reaching their verdict the magistrates said they were shocked at the case and had considered the potential implications of selling unsafe tyres.

In determining the penalties they said that they had considered a custodial sentence and if there were further offences it was highly likely to result in prison for the retailer.