Motoring experts have warned drivers who fill up with diesel are paying more at the pumps than they rightly should be.
According to the RAC, diesel drivers are "paying a huge premium" compared to those who have unleaded cars, although there is currently little difference between the two fuels on the wholesale market.
If you are one of the 12million people who drive diesel cars you will pay 20p more than someone filling up a petrol car at the pumps, warns the firm. However, RAC claims there's just one place drivers can find a better deal - Costco.