UK fuel prices have fallen for the fifth month in a row, according to the RAC.

However, the motoring organisation said diesel prices were still too high, based on wholesale prices.

The average cost of a litre of diesel came down by 4p in March to 162.94p – its cheapest price since March last year – while the average litre of petrol came down by a penny to 146.5p – a price last seen in January 2022.

However, the RAC has pointed out that during the month of March the wholesale price of diesel became lower than that of petrol, ending at 111.69p per litre versus 115.81p.

The organisation said it had calculated that the average retailer margin on a litre of diesel at the end of March was 21p, compared with 7p for petrol.

RAC spokesman Simon Williams said: “The fifth consecutive fall in the price of fuel in as many months is without doubt good news for drivers, but those who run diesel vehicles should have enjoyed far bigger cuts at the pumps than they have actually seen.

“It simply cannot be fair on drivers that the retailer margin on diesel is currently three times more than the long-term average at 21p a litre. While retailers are free to charge what they like for fuel we feel there should be an obligation on the those which sell the most, and therefore buy most frequently, to closely reflect what’s happening on the wholesale market. 

“If this had been the case then the forecourt price of diesel would have been down to around 152p a litre, even with an above-average margin.”