A petrol price war between the UK's top four supermarkets has started after Asda, Sainsbury's, Tesco and Morrisons announced lower petrol prices.

Asda and Sainsbury's said they would slash their petrol prices to as low as 94.9p a litre.

Tesco and Morrisons also said they would reduce their prices, while petrol company Total will follow suit.

The supermarkets have already joined battle on the issue of forecourt prices on several occasions.

'Rip off'

Sainsburys will cut its petrol prices by 3p per litre. While its prices are set according to local competition, it did say the majority of customers would pay 94.9p for unleaded and 106.9p for diesel.

No Sainsbury customers would pay more than 96.9p for unleaded and 107.9p for diesel, it said.

Sainsburys is supporting its announcement with a promotion offering an extra 5p off if customers spend £50 in store.

This could mean Sainsburys customers spend less than 90p a litre on fuel for the first time since April 2007, 

Meanwhile, Asda has said it will freeze prices in all of its 172 forecourts for 10 days. A litre of Asda petrol will now cost 94.9p, while Asda diesel will be 107.9p.

Tesco, Britain's largest supermarket, said it would cut its fuel prices by 3p per litre at the majority of its 430 forecourts. This marks its third price cut in two weeks.

Morrisons' price cut will be its second this week. On Monday it trimmed 2p off a litre, taking its prices down to 97.9p for unleaded and 109.9p for diesel.