Asda is the most expensive UK supermarket for fuel, according to new research.

Flling up car at petrol station

Asda was the most expensive supermarket for fuel in May, according to RAC

Average petrol and diesel prices at Asda were found to be higher at the end of May this year compared with its rivals TescoMorrisons and Sainsbury’s, according to motoring company RAC.

RAC said that, while global fuel prices are dropping, supermarkets are not passing these savings on to customers, the BBC reported.

In data submitted by the big four to the Competition and Markets Authority, RAC found that Asda was selling petrol at 146.34p per litre and diesel at 151.71p per litre.

This compared with 144.45p and 149.61p per litre at Tesco, Morrisons and Sainsbury’s – 1.9p and 2.1p less than Asda respectively.

RAC senior policy officer Rod Dennis said this was the first time Asda had come out on top of the most expensive list.

The motoring specialist added that, for many years, Asda had “prided itself on selling the cheapest fuel” but that it had now lost its “crown”.

Asda reportedly shut down the findings, saying they covered its whole estate, including convenience shops, and added that it still had the best prices at supermarket forecourts.

A spokesperson for Asda said: “Asda was the price leader in the supermarket fuel sector in May and we remain focused on providing our customers with the best value at the pumps as we grow in the convenience sector.”