Petrol prices: After a fall of 23p, Northern Ireland the cheapest in UK for fuel
Drivers in Northern Ireland are currently enjoying the lowest petrol and diesel prices in the UK - 23.6p per litre less than this time last year, according to the AA.
Northern Ireland has traditionally been at the opposite end of the scale.
But the AA said drivers in south west England, Yorkshire and Humberside, the north of England and Northern Ireland now get the lowest petrol prices, all averaging 108.8p per litre (ppl). 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.
It was only in August that Northern Ireland recorded the highest price in the UK for unleaded at 130.6p per litre.
In January last year, we were also the UK's most expensive for unleaded at 132.4ppl. Diesel was 135.9ppl - more than 20p a litre above the UK average.
But now average petrol prices have dipped to their lowest level for five years, the AA said.
However, the motoring organisation warned there was no guarantee prices would drop below the significant £1 a litre mark.
The AA said the average UK petrol price is 108.91p - a 7.41p dip on the mid-December figure.
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 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 with an 80-litre tank fell £4.84 this month, and is £16.21 cheaper to fill than in July when diesel hit its summer high of 136.37p.
AA president Edmund King said: "The supermarket price war that may have been a bit of a phoney in the past is a full-blooded fight now."
Earlier this week petrol was being sold for under £1 a litre at the Harvest Energy service station in Birmingham but brisk trade caused by the headline-grabbing price meant that the petrol pumps had run dry within a few hours.
According to owner Velautham Sarveswaran, the steep price cut was down to "a great deal" with his supplier.
He said: "It's a great feeling for me to be able to give cheap prices to my customers. I like making them happy."
RAC fuel spokesman Simon Williams said the Birmingham factor was "clearly having a ripple effect on the supermarkets".
He said: "We are surely only weeks away from the milestone price of £1 a litre being a common sight at petrol stations up and down the country."
The latest forecourt cuts come as Brent crude oil trades at about US$48 a barrel, the lowest level since April 2009.
US bank Goldman Sachs has lowered its forecast to $42 a barrel and said prices might remain at this level for some months due to the supply glut caused by investment in US shale wells.
The price slump continued to have an impact on FTSE 100 oil stocks, with BP shares down 2% in the session and by more than a fifth in the last year.