Petrol cheapest for five years
Average petrol prices have dipped to their lowest level for five years, according to the AA.
But it added that there was no guarantee that prices would go below £1 a litre.
The AA said the average UK petrol price is 108.91p - a 7.41p dip on the mid-December figure and only 0.5p short of the second-biggest monthly fall recorded by the AA.
Average mid-January diesel prices are 116.11p a litre, which represents a 6.05p cut on the mid-December figure.
These average figures do not take into account the latest 2p-a-litre reduction in petrol and in diesel by the four big supermarkets.
The AA said a family with two petrol cars is spending around £16.30 a month less at the pump than in mid-December, and more than £50 a month less than last July, when petrol was at 131.70p a litre.
The cost of filling a Transit-type van (80-litre tank) fell £4.84 this month, and is £16.21 cheaper to refuel than in July when diesel hit its summer high of 136.37p.
Drivers in south west England, Yorkshire and Humberside, the north of England and Northern Ireland are enjoying the lowest petrol prices, all averaging 108.8p a litre. East Anglia has the most expensive, at 109.4p a litre.
The average price of diesel is cheapest in Northern Ireland, at 115.7p a litre, while Scotland is most expensive, averaging 116.9p.
AA president Edmund King said: "A £50 cut to a two-car family's monthly petrol bill is a huge boost after more than five years of squeeze on the necessities of modern life, including fuel.
"This week, a £1 litre has appeared over the horizon although it's not guaranteed to appear in every town. In fact, many rural towns would say that predictions of petrol at 99.9p a litre are a bad joke as they continue to struggle with the pump price lottery.
" Even so, it has to be recognised that the supermarket price war that may have been a bit of a phoney in the past is a full-blooded fight now.
"Certainly, drivers increasingly gave them the cold shoulder through 2014, mainly because price-matching across a locality takes away the incentive to go specifically to a supermarket for fuel - unless it has rock-bottom prices."