The cost of diesel hit a six-year low during November, with petrol falling below £1 per litre.æ Meanwhile, the price of oil barrels also reached a similar low, declining to $40.40 per barrel.

Average costs of petrol also fell, reaching a five-month low. Diesel's average price was the lowest since late December 2009, reaching 109.48p per litre.

Since this time last year, the cost of filling up a 55-litre family car has decrease by £7.75 when using petrol.æ A tank of diesel has fallen even more, with a full fill-up now £8.95 cheaper than last year.

The RAC Fuel Watch report showed that a barrel of crude oil fell by over $3 during November.æ The pound did lose a little value to the dollar during the month, in turn impacting the profit margin, with oil traded in dollars.

Simon Williams, the RAC Fuel Watch spokesman, said:

'In the expensive run-up to Christmas, drivers of both petrol and diesel vehicles are benefitting from far cheaper fill-ups than they did at this time last year.î

'While petrol for under a pound a litre has become a reality at the cheapest retailers we would like to see this happen on a non-promotional basis. This depends, of course, on the cost of a barrel of oil staying low and ideally trading down a little closer to $40 for longer _ something which is very hard to predict, particularly as OPEC meet tomorrow in Vienna to discuss oil production strategy.î

'There has been talk of stabilising the barrel price which would mean stemming production, but it's difficult to see how that would work when Iran begins to pump up to one million barrels a day in 2016, following on from its landmark nuclear agreement with the West.î

'The lower forecourt prices we're enjoying at the moment are a product of the fall in world crude oil prices, which began in September 2014.î

'After a six-year low of $45 a barrel in early February and two instances of going back up to the $60 level twice briefly since, the price has been consistently below $50 since mid-October, reaching a new six-year low in mid-November.î

HMRC oil duty statistics for October showed that combined sales of petrol and diesel increased by 1.9 per cent when compared to the previous period.æ The month saw the fifth highest number of litres sold in any month since 1990.