For many drivers, the annual mileage is all guesswork when it comes to applying for car insurance, this is according to research from the price comparison website uSwitch.com.

According to their figures, drivers, on average, overestimate the distance between cities by 15%, equating to an additional 1,185 miles more than the 7,900 miles typically covered by motorists every year. And while overestimating your annual mileage could drive up your insurance premium, underestimating it could invalidate your cover.

Annual mileage is one of the key factors insurers use when calculating drivers' premiums, but just under a fifth of drivers refer to their MOT certificates, which provides the previous year's mileage when applying for a car insurance policy.

Rod Jones, insurance expert at uSwitch.com says: "While many of us are guilty of relying on gut feeling when providing our mileage information when applying for a car insurance policy, misjudging the number of miles you drive in a year can have a real impact on your wallet.

"If you drive fewer miles than you predict you could easily cut the cost of your next policy. That's why it pays to dig out your MOT certificates to pinpoint the number of miles you drove last year to help you to provide a more accurate estimate for the one coming up."