Fuel prices are falling but the RAC says major retailers are not reducing in line with falling wholesale costs.

The roadside recovery firm said wholesale cost of unleaded – the price when it arrives at forecourts – is now back down to its early May price of 131.75p per litre, which saw average pump prices of around 167p per litre.

But drivers are paying an average of 183p per litre at pumps across the UK despite the drop in wholesale costs, the RAC said.

This means drivers filling up at that end of July average of 183p per litre could be paying almost £9 a tank more than they should be.

Equally, the firm said drivers should now be paying about 182p per litre for diesel – nearly £6 a tank lower than the end of July average of 192p per litre.

The ‘big four’ supermarkets – Tesco, Asda, Morrisons and Sainsbury’s, along with several other suppliers – have been facing criticism for failing to reduce their prices in line with falling wholesale costs.

RAC fuel spokesman Simon Williams said: “July has been an unnecessarily tough month for drivers due to the big four supermarkets’ unwillingness to cut their prices to a more a reasonable level, reflecting the consistent and significant reductions in the wholesale cost of petrol and diesel.

“As it was, we saw independent retailers leading the charge with fairer pump prices appearing all around the country which eventually forced the supermarkets to finally implement a more substantial cut late last Friday afternoon.”

However, a supermarket price war appears to have kicked off this week, with Tesco slashing the cost of petrol and diesel by between 8p and 9p a litre.

Locally, petrolprices.com shows that the Morrisons and Asda stores were offering the lowest price in the Norwich area on Tuesday, at 174.7p, with Tesco and Sainsbury slightly higher at 174.9p per litre.

It shows a similar story in King’s Lynn, with Morrisons and Asda cheaper on Tuesday at 178.7p ahead of Tesco at 178.9p and Sainsbury at 181.9p.

While in Great Yarmouth, the Shell garage in St Nicholas Road is shown as cheapest on Tuesday (175.9p), with Asda at 176.7p and both Tesco and Morrisons at 176.9p.