A major UK supermarket has cut its petrol prices by almost 5p per litre, while diesel prices have been cut even further.

Asda decreased the cost of petrol across its 320 UK filling stations by an average of 4.5p per litre in the past two days, but according to the RAC it should have happened “much sooner”.

Diesel prices have been cut by an average of 5.5p per litre.

Asda did not announce it was making the price reductions.

RAC fuel spokesman Simon Williams said: “While we’re pleased one major supermarket retailer has finally started heeding our calls to pass on the enormous drop in the wholesale prices of both fuels, the fact these price cuts have been made so quietly is surely admission that they should have come much sooner.

“Asda is now charging an average of 153.5p for petrol and 176.7p for diesel which is around 2p less than its rivals.

“We urge the other three supermarkets to catch up quickly – or go even further – and give drivers some much-needed relief from high prices next time they fill up.

“If they do, this will bring the UK average petrol price down from its current 157.8p which benefits drivers everywhere.

“Despite these reductions, our analysis of wholesale data shows this should really be just the beginning as there’s easily scope for another 10p a litre to come off the current average price of both petrol and diesel.

“Perhaps it will be Asda which once again takes a leadership position by further cutting its prices to help drivers save money in the run-up to Christmas.”