If you normally fill up your car at Asda, Sainsbury's or Tesco, hold off until tomorrow if possible as the supermarkets plan to cut petrol prices by up to 2p/litre.

Asda kicked off the fuel price war this morning with the announcement that it will cut diesel prices by up to 2p/litre and unleaded by up to 1p/litre, beginning tomorrow.

As Asda sets a national price cap across its 232 forecourts, drivers will pay no more than 126.7p/litre for diesel and no more than 123.7p/litre for unleaded. The supermarket says the move comes as the price of oil "slides to under $90 a barrel".

Sainsbury's quickly followed Asda's lead by also announcing diesel price cuts of up to 2p/litre and unleaded cuts of 1p/litre across its 295 forecourts from tomorrow.

Tesco then said it too would cut prices from tomorrow at all of its 500 petrol stations. Unleaded prices will fall by 1p/litre, while diesel prices will be cut by at least 1p/litre, with some petrol stations getting a 2p/litre price reduction.

MoneySavingExpert.com has asked Morrisons if it plans to do the same and we will update this news story as soon as we hear anything.

However, tomorrow's price drop doesn't necessarily mean these supermarkets are the cheapest fuel providers. To find the lowest price in your area, use the website Petrolprices.com and see our Cheap Petrol and Diesel guide for more ways to save when filling up your tank.

According to the latest figures from Petrolprices.com, the average UK price for a litre of diesel was 131.88p/litre last Thursday (9 October), while the cost of unleaded petrol stood at 127.69p/litre.