Risks of buying a used car

Outstanding finance: If money is still owed by anyone who bought the car before you, the finance company can seize it. Half of new cars are bought on finance, and one in four used cars checked on AutoCheck has a finance agreement recorded against it.

Write offs: Insurers write off a car when they think it will cost too much to repair, or when they've paid out on a theft claim but haven't found the car (which means the insurer now owns it). The ownership and safety of write offs needs to be carefully checked before you buy one. One in eight cars checked using AutoCheck is an insurance write off.

Third-party trace: Experian keeps a database of vehicles that finance companies, insurers and others are trying to track down - either because money is owed on them, an insurance claim has been made, or because a fraud has been reported. There are 190,000 vehicles on the Experian high-risk database - all of which could be involved in theft or fraud.

Stolen cars: If you buy a stolen car, it remains the property of the original owner who can reclaim it - you'll be left with no car and no compensation. 160,000 vehicles a year are reported stolen.

Clocking: Winding back the odomoter to make the car appear better value is another risk. One in 14 vehicles checked through AutoCheck have a mileage discrepancy.