Supermarket Asda is dropping the price of unleaded petrol on Friday - despite saying it would not take part in the Black Friday discount day.

It is knocking four pence off a litre of fuel across its 277 petrol stations for three days, and drivers can expect to pay 99.7ppl on unleaded and 103.7ppl on diesel.

That includes the Asda forecourts in Totton and Chandler's Ford

The price cut takes the cost of a litre of unleaded petrol below £1 for the first time since 2009.

On Monday, Asda will revert back to its original price of 103.7p on unleaded and 106.7 ppl on diesel.

The supermarket chain had earlier said it was not going to take part in Black Friday after chaotic and violent scenes in its stores last year.

Asda is owned by US giant Walmart and was one of the original retailers that helped to bring the Black Friday phenomenon from the US to the UK.

The discounts will have added impact following the freeze on fuel duty announced in the Autumn Statement on Wednesday.

However Edmund King, AA president, warned that a cut in fuel prices beyond Black Friday is what is really needed to help UK drivers.

He said: ''Apart from marketing gimmicks, pump prices haven't been below £1 per litre for five and a half years.

''Some drivers may wonder why petrol isn't one pound per litre across the board with oil trading at under 50 US dollars per barrel.''

Asda president and CEO, Andy Clarke, said: ''The Chancellor's freeze on fuel duty is what our customers were hoping for. We'd urge the Chancellor to continue with a freeze on fuel duty in the March Budget to help maintain discretionary income levels for families.''

RAC spokesman Simon Williams said: ''Due to the latest dip in the crude oil price we had predicted that the most price-competitive fuel retailers would soon be selling petrol for £1 so it is great to see that landmark price is now available across the country at the most expensive time of year.

''Even though this promotion only lasts for three days it will help to bring prices down at forecourts nationwide.

''While we are some way from seeing the average petrol price reach £1, prices at more and more retailers should be getting ever closer to that figure.''