The UK's four biggest supermarket chains are all cutting up to 2p off a litre of petrol and diesel in a pre-Christmas price war.

Fuel from Asda, Sainsbury's, Morrisons and Tesco forecourts will be cheaper from tomorrow morning.

Asda, which was the first to announce a cut, says this is because wholesale prices — the amount it pays for the fuel it sells to motorists — have fallen, allowing it to reduce pump prices.

Drivers filling up at any Asda forecourt will pay no more than 131.7p per litre of unleaded from tomorrow, and no more than 137.7p per litre for diesel. Other supermarkets' prices are set locally so can vary.

The reductions do not necessarily mean any of the supermarkets will become the cheapest fuel provider. The website Petrolprices.com lists the cheapest in your area.

The site reports average petrol prices on Tuesday were 136.50p per litre, while the average diesel cost was 143.06p per litre.

This is slightly down on 22 October, when petrol was 138.76p per litre on average, with diesel at 143.72p. That week also saw supermarkets cut fuel prices.