Petrol stations are overcharging drivers by a minimum of Â£2.50 per tank, a new report has found.
Analysis from FairFuel UK found the price of petrol and diesel had surged by 5p a litre since early May while wholesale costs have risen by only a fraction of a penny.
Fuel retailers are enjoying a Â£500 million windfall while drivers are stuck paying Â£2.50 extra for a 50-litre tank.
While these increases were initially sparked by rising oil costs and a weaker pound, the Brent Crude price has since fallen back. This has not resulted in any reductions in the price at the pump, leading to criticism for industry experts.
Commenting on the situation, RAC fuel spokesman Simon Williams described May as a â€œhellish month for motoristsâ€.
AAâ€™s fuel spokesman Luke Bosdet explained: â€œLess than a month ago, the petrol retailers were falling over themselves to warn of pump prices at record levels. â€œNow that the price of oil has fallen away and fuel costs have followed, in true form they have kept quiet and carried on charging cash-strapped motorists the maximum for their fuel.â€
The news comes after it was revealed that motorists were being charged up to 20 pence more per litre for filling up outside of city centres.
Scottish Conservative MP and chair of the FairFuel APPG, Kirstene Hair, is calling for the UK Government to look at fuel duty cuts for more rural areasÂ and to set up an independent price monitoring body.
Expressing her view on the situation Ms Hair said: â€œIt is unfair that retailers are increasing costs disproportionately for hard-working families, small businesses and the haulage industry.
â€œWe need an independent price monitoring body, this will ensure households and businesses are no longer charged unfairly for fuel.â€
The latest figures include cuts of up to 3p introduced last week by Tesco, Sainsburyâ€™s, Morrisons and Asda.