The cost of petrol and diesel will be cheaper for those filling up at Tesco and Asda from tomorrow, but Morrisons and Sainsbury's won't be cutting prices at the pumps.
Motorists have been given respite from rising petrol prices after Chancellor George Osborne announced an extension to his fuel duty freeze until May 2015.
The Financial Conduct Authority is to investigate price comparison websites to find out if they are misleading customers by promoting deals they want them to buy.