The end of the war is cited as one reason for cheaper petrol

Forecourt petrol prices are falling for the third week running.

Supermarket chain Asda has cut its prices by 1p a litre and rival stores Tesco, Sainsbury and Morrisons say they will follow suit.

The supermarkets' price-cutting battle for customers follows the end of the Iraq war and a fall in the cost of oil.

The price of crude oil has fallen by more than $10 a barrel, or 30 percent, since it peaked at $34.55 per barrel, a few days before the war on Iraq was launched by U.S. and British forces in mid-March.

'Very positive'

The latest reduction takes the average price for a litre of unleaded fuel at Asda's 152 forecourts to 73.4p, with diesel at 75.7p.

Tesco confirmed it would follow Asda's lead and Sainsbury's said it would match the petrol prices of its rivals in a "large number of stores".

But Morrisons claimed to have the lowest petrol prices in the UK, after a price cut of more than 2p per litre.

Unleaded petrol was down to 72.9p per litre and diesel 74.9p per litre at all Morrisons 102 petrol filling stations.

The price cut of 10p a gallon was effective in all Morrisons petrol stations from the start of trade on Friday, 2 May.

Further reductions?

Shell said it would match prices wherever it competed with supermarkets, while Esso had a pledge to be "among the lowest" within a three-mile radius of its stations.

Other major petrol companies were expected to monitor the situation.

Ray Holloway, spokesman for the Petrol Retailers' Association, said he hoped to see a competitive market benefit drivers.

He said: "I think we will see prices drop steadily over the coming weeks rather than instantaneously."

Announcing the latest price cut Asda director Paul Mancey said: "Asda has demonstrated in the last fortnight its commitment to the lowest possible fuel prices."