Three of Britain's biggest supermarkets have launched a petrol price war.

Supermarket chain Asda has announced it would cut the cost of unleaded and diesel by 3p a litre, and Morrisons has followed by cutting the price of unleaded and diesel by 4p a litre.

Sainsbury's said it was cutting petrol by 5p a litre from Thursday for customers who spent £50 or more in stores. The promotion will run for two weeks.

Asda and Morrisons said they were responding to the recent drop in the price of oil.

The price of a barrel of oil dropped from a peak of $147 to $130 in recent weeks.

Asda said all 170 of its petrol forecourts across the country would sell unleaded petrol for 113.9p a litre and diesel for 128.9p a litre from this morning.

Asda trading director David Miles said: "We are seeing a more stable reduction in oil prices, allowing us to pass on the savings to customers.

"We urge other retailers to follow our lead at a time when customers need as much help as possible."

Morrisons later said it would cut the cost of unleaded and diesel by 4p a litre at all of its 285 forecourts across the UK.

Morrisons group store operations director Mark Gunter said: "The cost of crude oil and refined product has fallen in the last few days and we are ensuring our customers reap the benefit by passing on the saving quickly, for cheaper prices at the pumps."

A spokeswoman for Sainsbury's said: "From Thursday our customers can reap an even bigger reward because we are running a 5p off per litre promotion when they spend £50 or more in-store plus they will also earn Nectar points."

AA president Edmund King said: "Asda's petrol price drop is excellent news for UK motorists and we urge other fuel retailers to reduce their prices - and not only where they find themselves neighbouring an Asda petrol station.

"We have seen two drops in European wholesale fuel prices so far this summer with the UK motorist seeing next to no benefit. Since mid July the wholesale gasoline price has fallen 6% and the AA expects fuel suppliers to pass on, not pocket, the saving for the good of UK families, hauliers and the economy.

"We will watch price movements like a hawk, and should fuel suppliers and retailers appear to be dragging their feet we will seek to expose this."

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