Companies that encourage their staff to drive more efficiently could save themselves £250 a year per driver and benefit from greater staff motivation, according to the Energy Saving Trust.

The organisation estimates that the UK could save £5bn a year in reduced fuel costs and cut carbon emissions by 10m tonnes a year if every driver drove smarter, for example by using cars at their most efficient speeds.

"Smarter driving means driving more efficiently, which in turn can lead to reducing fuel usage by an average of 15% and a typical annual saving of between £200 and £250 per person," said Philip Sellwood, chief executive of the Energy Saving Trust.

"If everyone started driving smarter we as a nation would save ourselves £5bn. At times like these that's not to be sniffed at."

The body added that 44% of British workers said they would be more motivated if their employer offered some kind of green benefit, while a third said their job was the main reason why they did not have time to be green.