The price of diesel at the pumps is still not being cut quickly enough, according to the RAC.

In late February the drivers of diesel vehicles were being asked to pay 20p more for a litre of fuel than petrol. The difference in wholesale cost between petrol and diesel is just 6p, and the disparity is fuelling accusations that the major retailers and supermarkets are profiteering at the expense of diesel drivers.

RAC’s Fuel Watch data revealed that the average price of diesel was 168p on 20 February, and the wholesale cost was 121.06p, meaning that retailers are doubling the margin per litre of diesel, compared to petrol.

The RAC calculates that if diesel was being sold at a fairer rate drivers would be paying no more than around 155p per litre, which would make the cost of filling an average 55-litre family car £7 less than it is today (£85.25, compared to the current £92.40).

“For nearly a month, the gap between wholesale petrol and diesel prices has been less than 10p a litre and in recent days it has reduced to just 3.5p,” said RAC fuel spokesman Simon Williams. “Yet average diesel prices at the pumps remain stubbornly high having fallen by only 2p since the start of February.”

“Even though the price of diesel is not being cut as quickly as it should be, the gap between the average prices of petrol and diesel has dropped to under 20p (19.99p) for the first time since 10 October 2022. If retailers now do the right thing this should reduce significantly, saving drivers who rely on diesel a lot of money every time they fill up.”

Membership-only retailer Costco slashed their diesel prices by 4p in late February, a move that convinces the RAC that there is capacity for diesel prices to come down more widely across the UK.