Many fuel retailers are expected to cut the price of petrol to £1 a litre in time for the Christmas getaway. The RAC believes the tumbling oil price will lead to a 3p drop for petrol and 5p for diesel.
This would take average prices to around 103p for petrol and 104p for diesel, but experts predict prices will be lower at many forecourts.
RAC spokesman Simon Williams said: "We expect Britain's supermarkets and cheapest fuel retailers to be selling petrol at £1 a litre or less in time for Christmas.
"These retailers consistently tend to be 3p-5p a litre cheaper than the UK average price. We are still some way off the average price of unleaded reaching the £1-a-litre mark, but this will be a big step in the right direction."
Tesco and Asda announced yesterday that they have slashed petrol and diesel prices by 2p a litre, while Sainsbury's said it would cut its prices by "up to 2p".
Recent savings have been attributed to oil prices slumping to a near seven-year low, with a barrel of Brent crude falling below 40 US dollars earlier yesterday.
The average price of diesel is already at a six-year low, dropping to 109.18p on Friday.