32.17% of finance checks conducted by My Car Check in the first half of 2015 showed money was still owed on the car.

Percentage of My Car Check checks showing active finance agreements:

Head of CDL Vehicle Information Services (which owns My Car Check) Roger Powell said: "While innocent purchasers can and do fall foul of traditional threats like clocking, there is at least a decent level of awareness about them. By contrast, there is a serious lack of awareness about the risk of buying a second hand car with second hand debt. We need to get the message out that outstanding finance is now by far the most common pitfall awaiting UK used car buyers.

"Certain types of agreements, such as the increasingly popular Personal Contract Purchase (PCP), usually involve the debt being secured against the vehicle, rather than the individual. This means a lot of the cars on our roads actually belong to a finance company, not the people who drive them. Attempting to sell a vehicle owned by a finance company, an activity called sub-hiring, is illegal, but very common. Some sellers do it knowingly. Others wrongly believe that everything will be fine if they keep up the payments. The crux for buyers is that the finance company can be within their rights to seize the vehicle back.

"For the price of a few litres of fuel, our finance data can be the difference between buying a vehicle completely legally and being left hugely out of pocket with no car to show for it. Particularly in the private marketplace, many sellers are keen to pass the problem on, having inadvertently taken on a car with second hand debt themselves."