More than seven million illegal cars are being driven on UK roads, according to new research.
Defects from bald tyres to missing wing mirrors are just some of the law-breaking faults that drivers are prepared to ignore.
Research from breakdown service Britannia Rescue suggests that motorists delay repairing these potentially fatal faults by an average of four months with one-in-seven waiting six months.
Younger motorists are the worst offenders, with 25% of 18-34 year olds driving an illegal car. The figure for those over 55 falls to just 5%.
The research also revealed that 20% of motorists had driven a car without a valid MoT certificate, with a third of those doing so knowingly.
The Institute of Advanced Motorists (IAM) is calling on the Vehicle and Operator Services Agency (VOSA) to extend the MoT certificate reminder scheme, to stop offending drivers claiming ignorance as a defence.
IAM director Neil Greig said: In 2010, poorly maintained vehicles caused 52 road deaths. Neglecting maintenance only leads to bigger repair bills later on, lower second-hand values and increased fuel consumption. There are also fines if you get caught.