Research suggests 80% of drivers have increased the chances of their vehicles being broken into by leaving valuables in their cars.
According to the report by car insurance firm LV=, high-value items such as mobile phones, clothes and even wallets are regularly left inside vehicles whilst parked on UK roads, while a quarter of UK drivers reported being a victim of a car break-in.
The value of goods left by men adds up to an average of £380, much higher than that of more safety conscious women.
Younger drivers are particular careless, with drivers aged 34 or under admitting to leaving an average of £334 worth of goods in their vehicle, compared to a national average of £283.
Cars are most at risk of being broken into whilst parked on residential streets, with 40% of all thefts taking place whilst the car is parked directly outside the owners' home.
Emma Holyer, spokesperson for LV= Car Insurance, said: "Most car break-ins are by opportunist thieves who would probably not bother to break into the car if it looked as though it didn't contain anything."
© Press Association 2008