Motorists buying more efficient cars aren't really making any fuel cost savings due to the rising prices at the pumps.

Data from The Miles Company shows that, although today's average company car covering 10,000 miles uses 13% less fuel than its 2004 counterpart, higher pump prices mean that it costs just as much to keep it fuelled.

TMC calculated the cost of fuelling a car over 10,000 miles, based on inflation-adjusted fuel prices and the average CO2 rating of new cars acquired by fleets each year, from 2004 to the present.

The 2010 fuel bill is marginally higher, even though the CO2 from new cars (and therefore their fuel consumption) has fallen from 167g/km to around 145g/km.

“The message is clear. Businesses that intend to cut their fleet costs cannot afford to rely solely on more efficient company cars,” said Paul Jackson, managing director of TMC.

“While the most fuel-efficient cars – those in the sub-120g/km CO2 bracket – are holding their own in the race against higher fuel prices, the average new car is being left behind,” he said