There was good news for motorists planning a bank holiday getaway today, as supermarkets continued their petrol price war with another round of cuts.

Asda sparked the third set of price reductions in a fortnight with its announcement yesterday that it would be cutting 2p a litre from the cost of unleaded petrol.

The chain is reducing unleaded from 93.9p a litre to a flat rate of 91.9p a litre, its lowest price since May, and diesel from 95.9p to 93.9p.

Tesco said it would match Asda's latest offer but could not put a figure on its reductions because it operates a local pricing policy.

Sainsbury's pledged to follow suit today by either matching or beating its rival on price, despite its own regional pricing policy.

The latest wave of reductions follow cuts brought in by Tesco, Asda and Sainsbury's last week and over the weekend.

The retailers said reductions in the wholesale price of crude oil were behind the lower petrol prices.

Asda trading director, Andy Brem, said last night: "We guarantee that we will be quick to pass on cost savings to our customers and today we are delivering on this commitment by offering the lowest pump prices in the UK."

Kay Joyce, spokeswoman for Petrolprices.com, a website which helps drivers find their cheapest local filling station, said the supermarkets were helping to drive down prices across the board.

"Our stats are showing us that the oil companies are coming in and cutting prices as well," she said.

The AA Motoring Trust said a further round of price cuts was unlikely unless the price of crude oil began to come down.

Ruth Bridger, petrol price analyst for the trust, said the last time supermarkets got involved in a price war was when the oil prices started to come down from the spike caused by Hurricane Katrina.

This time oil prices haven't fallen, but she said the supermarkets may well be counting on them doing so as tensions in the Middle East ease.

She added: "Hopefully for the motorists the price of a litre will continue coming down, but until oil prices are steadily in the $60s [per barrel] rather than the $70s it is not going to fall much lower than it is at the moment."

In July, motorists were facing record prices for petrol as problems in the Middle East drove up oil prices.

The average price of unleaded reached 96.85p a litre and in some areas of the country drivers were paying up to £1.07 a litre.