Despite the average cost of fuel rising for a fourth successive month, making petrol 11p a litre more expensive and diesel 7p more expensive than in February, there is a belief that the price of diesel could be cut by as much as 6p a litre to aid the back pockets of fleets nationwide.

According to new data from RAC Fuel Watch, the average price of petrol at the pumps rose by 2.34p to 130.57p last month, with diesel also rising 1.74p to 135.54p per litre.

It’s been almost five years since unleaded petrol was this expensive at the pumps, although diesel did reach 136.94p a litre on average back in October 2018.

Ultimately, the cost of filling up a conventional 55-litre diesel fleet car has risen to £74.55, some £3.80 more than in the previous quarter. This is a substantial increase in overheads for fleets with multiple vehicles on the road each week.

The RAC is particularly frustrated at the rising price of diesel at the pumps, given that its comparatively low wholesale price has led to calls for substantial price cuts on the forecourts.

By the end of May, the price of crude oil was trading as low as $65. Simon Williams, fuel spokesman for the RAC, believes this should “soon translate to lower prices at the pumps”.

“After suffering a steady flow of daily fuel price increases because of rising wholesale costs, we urge retailers to reflect this sudden drop in the price of oil by cutting their prices as soon as possible,” added Williams.

“The price of diesel has been over-inflated for more than a month. In fact, the wholesale price of diesel has now been lower than petrol since 17th May, yet there is currently an average difference of 5p between the two on our forecourts.

“Consequently, there is scope to cut the price of diesel by at least 6p a litre. In reality, however, the majority of retailers will no doubt refuse to do this and instead continue to use the saving from the lower diesel wholesale price to subsidise the ‘headline’ petrol price with a view to attracting more customers to their forecourts and stores.”

According to RAC figures, the East Midlands was hit hardest by rising diesel costs last month, with a 1.95p rise to 135.81p per litre. The south-east of England has the most expensive diesel for fleets at a cost of 136.46p per litre. Meanwhile Northern Ireland boasts the cheapest diesel for fleets at a cost of 132.56p per litre.