Fleets are being urged to make the most of the current low petrol and diesel prices at the pumps as data from the RAC's Fuel Watch January report indicates the cheap fuel market is at risk of bottoming out. Oil barrel prices fell to a 12-year low of $26 on Weds 20th January, but since then the barrel price has shown signs of rebounding, finishing January at $33.12 _ only $3 lower than where it started the year at $36.54. This late fluctuation at the end of last month has caused the wholesale cost of petrol and diesel to rise again, although diesel still remains some 3p a litre cheaper than unleaded petrol. Nevertheless, January remained a landmark month for diesel prices with 5p a litre falling off the average pump price with many supermarkets slashing prices to 99.9p a litre and then below 98p. Simon Williams, fuel spokesman, RAC, said: 'Motorists have seen petrol and diesel prices reach their lowest points since 2009. 'January saw the oil price go into free fall with talk of a barrel dropping to $20 and possibly even to $10, but since the low of $26 a barrel, the market has started to creep back up. 'If this continues for a sustained period, wholesale costs will rise further which will in turn lead to pump price increases. 'However, the oil market is notoriously volatile, even in more stable economic times, so it's still possible that the price could drop back again. 'And, even if there is a rise in the oil price, it seems unlikely that it will be drastic as OPEC seems set to continue producing more oil than is demanded to retain its market share. 'While there has been talk of a production cut, the market has yet to see evidence of this. 'The other factor which is not helping the situation from a motorist's perspective is the fact that the pound has weakened significantly against the dollar from $1.47 at the beginning of January to $1.42 by the end [of the month]. 'This has undermined some of the benefit of the falling oil price and, with oil traded in dollars, this could prove to be even more harmful if the pound continues to lose value against the dollar while the oil price goes up.î Data from HM Revenue and Customs (HMRC) for December 2015 shows combined sales of petrol and diesel were 1.8 per cent down on November at 3.938 billion litres, but 0.4 per cent up year-on-year (December 2014). More petrol was used in December 2015 than in the previous month, with 1.458 billion litres compared to 1.437 billion; a 0.8 per cent year-on-year increase (December 2014). However, diesel usage fell month-on-month by 3.7 per cent from 2.574 billion litres in November to 2.480 billion litres in December; but remained unchanged when comparing year-on-year.