Asda has become the UK’s most expensive supermarket for fuel, new analysis has found.

A litre of petrol at Asda cost an average of 2.1p more on average than rival supermarkets Tesco, Morrisons and Sainsbury’s, the RAC has said.

The difference in average diesel prices was even steeper, at 2.5p per litre.

The RAC analysis found that across all UK forecourts, the average price of petrol fell by 2.4p per litre last month to 147.9.

Diesel prices dipped by 4.5p per litre to 153.6p.

RAC senior policy officer Rod Dennis said pump prices should be falling much faster to reflect a decline in wholesale costs.

He said: “A month of decreasing fuel prices should be seen as a good one for drivers but the sheer time it is taking for any meaningful price reductions to reach forecourts is if anything a continuing cause of concern.

“When it comes to much-needed pump price cuts, it’s sadly a case of too little too leisurely, with most drivers still getting a miserable deal every time they fill up.

“We’re once again in classic ‘rocket and feather’ territory, with pump prices only trickling down when they should really be falling like a stone.

“It’s also interesting to see that Asda no longer holds the crown for selling the cheapest fuel despite the pledge made when it was subject to a merger a year ago.

“The other three major supermarkets, as well as some enterprising independents, now offer lower prices.”

Asda was approached for a comment.

Top 5 tips to save money on fuel

Experts from Swansway Motor Group have outlined 5 money-saving tips for motorists grappling with rising fuel costs.

Check your tyre pressure

Maintaining the correct tyre pressure is essential for vehicle efficiency. Under-inflated tyres can lower mileage and increase fuel usage. It's recommended to check tyre pressure monthly, as proper inflation improves vehicle safety and extends their life.

 Keep your windows closed if driving over 40mph

 At higher speeds, keeping windows closed reduces aerodynamic drag. While the impact on fuel efficiency can vary depending on vehicle design and driving conditions, reducing drag helps maintain better fuel economy at highway speeds.

Turn off the air conditioning

Air can increase fuel consumption by using significant engine power. When you first get into your vehicle, open the window to lower the temperature of the cabin, then if you are to use the aircon it won’t have to work as hard to cool the car down. Likewise, it’s more efficient to switch to aircon when driving at speeds over 40mph. 

Avoid idling

An idling engine burns fuel without moving, which clearly wastes petrol and increases wear and tear on the engine. It's recommended to turn off the engine during prolonged stops to avoid unnecessary fuel consumption.

Remove unnecessary weight from your vehicle

Extra weight in a vehicle causes it to consume more fuel. Reducing the weight can improve the car's miles per gallon.

The experts explained: “It's concerning to see the retailer margins on fuel; unleaded petrol margins have reached 9.5p per litre, and diesel even more dramatically at 18p per litre, which is a significant rise of 6p in April alone.

“These figures markedly exceed the long-term average margin of 8p per litre. Such disparities are leading to increased running costs for consumers and businesses”

"The variability in fuel prices is another pressing issue. Analysis shows that the differences between the cheapest and most expensive fuel ranges from 8p to 36p per litre in supermarket fuel prices at the end of April.

“This not only complicates budgeting for consumers but also highlights the need for more regulated pricing policies to help with such extreme differences”

"Reflecting on the pricing trends, the lowest prices this year were recorded on January 16, with petrol at 139.7p per litre and diesel at 147.6p per litre.

“The significant rise from these lows to current rates underscores the volatility in the fuel market and the direct impact on our customers."