Britons waste £456m a year on bad purchasing decisions when it comes to used cars.

According to research from car retailer Network Q, consumers are throwing money out the window by not shopping around for better advice and deals, with an average of 28 per cent of car decisions ending in regret.

More than 32 per cent of respondents quote lack of knowledge' of used cars as the main reason for making bad purchasing decisions, while nearly a quarter claimed untrustworthy sales people were responsible.

If they had the opportunity to do things differently, 45 per cent would insist on an approved mechanical check before purchasing.

Mike Brown, of Network Q, said: "If you want to avoid the risk of making a bad purchase always go to a reputable, national retailer, one you can trust and demand a 114 pt check on every car."