Asda charges 2.1p more for petrol and 2.5p more for diesel than rivals, according to RAC analysis.

UK's most expensive supermarket fuel retailer revealed: Asda charges 2.1p more for petrol than rivals Tesco, Morrisons, and Sainsbury's, and 2.5p more for diesel, according to new analysis by the RAC. Historically, Asda has been known for offering the cheapest fuel. The RAC found that the average cost of a litre of petrol dropped 2.4p last month to 147.88p, while diesel prices fell 4.5p down to 153.58p per litre.