The PRA has accused supermarkets of aggressive, anti-competitive pricing after Morrisons and then Asda slashed their fuel prices, with 12ppl off petrol and 8ppl off diesel.

Asda said that the cuts would mean drivers would pay no more than 102ppl for petrol and no more than 108ppl for diesel, and that it was passing on reductions due to the plummeting cost of oil.

While many supermarkets get daily fuel deliveries, massive reductions in fuel volumes for most dealers, as motorists have stayed at home due to coronavirus, mean that many still have petrol and diesel in their tanks that was bought at much higher prices.

PRA chairman Brian Madderson said: “There has hardly been any volume this week so dealers could not possibly afford to give away fuel at the prices the supermarkets were charging. Dealers need to keep their businesses going and to pay their staff. Smaller businesses nearer supermarkets are going to feel the pinch.”

Even the RAC, which is usually urging supermarkets to cut fuel prices, only gave a muted welcome to the latest cuts.

RAC fuel spokesman Simon Williams said: “These unprecedented times are leading to unprecedented price cuts on fuel – the largest single cut from a retailer we’ve ever seen. The price of oil has fallen so far – down to an 18-year low – that it was inevitable that pump prices would eventually follow suit.

“Drivers can expect to see petrol sold at supermarket forecourts for around 104ppl as a result of these cuts, a price last seen nearly four years ago. Diesel should drop to around 111ppl, and it was last sold at this sort of price in July 2017.

“However, there is a darker side to these price cuts. Smaller independent forecourts, which will already have been struggling due to a loss of trade recently, will be extremely hard-pushed to reduce their prices at the present time with fewer people driving. It’s crucial they stay in business as they provide such an important service to drivers in parts of the country where the supermarkets have no footprint.”