Asda has sparked a petrol price war among the supermarkets, dropping prices for the second time in a week.

It has dropped unleaded petrol to 91.9p a litre and diesel to 93.9p a litre. Last week it cut prices by 4p a litre.

Andy Brem, trading director at Asda, said: “We guarantee that we will be quick to pass on cost savings to our customers.”