Government proposals to scrap the annual MoT test will cost motorists dear, according to Stuart Carr of the HiQ fast fit network.
Secretary of State for Transport Philip Hammond has said he wants to introduce the initial MOT test for new cars after four years instead of three, and to continue testing every other year rather than the current 12 month period.
Mr Carr said: 'The Government is claiming that by considering this change, consumers will save money because modern day cars don't need their vehicles tested as often.
'The worry is that within the extended interim period, motorists will be driving around with defects that could have more severe costs to repair when the vehicle gets tested.'
He added: 'We always call for improvements to the benefits of our business, but in this case, it is important to clarify that we are campaigning on behalf of the consumer, for money saving and safety.
HiQ is calling for car owners whose cars have failed their MoT to send their local MPs photographic evidence of dangerous parts such as worn brakes and tyres.
It is also compiling a 'chamber of horrors' with which to lobby ministers.