New data from ALD Automotive, which operates a fleet of around 50,000 vehicles, reveals that average CO2 emissions of new company cars delivered to customers dropped to an all-time low of 145.5g/km last year.

That compares with an average figure of 150.5g/km in 2008 and 166.8g/km in 2003.

Month-on-month last year the average CO2 emissions for new company cars supplied by ALD was consistently below 148g/km and the last three months averaged 145g/km (October), 143g/km (November) and an all-time low of 136g/km in December.

The data also reveals that the average emission level of company cars added to ALD’s fleet is lower than the national average of new car CO2 figures as produced by the Society of Motor Manufacturers and Traders.

Last year average CO2 emissions for all new cars taking to the UK’s road fell to 149.5g/km (2008: 158g/km), according to SMMT data. The 5.4% fall in average new car emissions last year was heavily influenced by rising private sector sales, particularly of small low emissions cars, as a result of the scrappage incentive scheme.

Meanwhile, company cars added to the ALD fleet are also clocking up less mileage, according to the analysis.

It reveals that in 2003, the average annual contracted mileage for company cars was 22,475 miles, but in 2009 the average had fallen to 18,204 miles - a reduction of more than 4,000 miles a year.

The ALD data also highlights that the average contract hire agreement signed last year was for 38.5 months and just over 58,000 miles.

Undoubtedly, says ALD, the continuing trend towards low emission company cars has been significantly influenced by the Government’s decision to link all motoring taxes - benefit-in-kind tax, Vehicle Excise Duty and most recently capital allowances - to vehicle CO2 levels.

Fleet decision-makers ensuring low CO2 emitting company cars dominate fleet choice lists also helps cut company and driver fuel bills as the lower a model’s emissions the better its MPG performance.

Meanwhile, improved travel planning and mileage management by both businesses and company car drivers as a result of a focus on carbon footprint reduction has contributed to the steady decline in journey distances in recent years.

The expectation is that average CO2 emissions for new company cars will continue to decline.

ALD Automotive marketing director David Yates said: “We have witnessed a huge shift in the last seven years in the make-up of our fleet in terms of both the type of company cars increasingly chosen by businesses and their drivers, and the amount of mileage clocked up.

“The economic downturn increased the spotlight on the cost of motoring from both a fleet management and driver perspective. Coupled with the Government using motoring taxes to influence the take-up of low emission company cars, there is no doubt that we expect average CO2 figures to fall further in 2010.

"Indeed the downward shift in company car emissions may even accelerate as motor manufacturers increasingly use a wide range of new technology to cut petrol and diesel vehicle CO2 emissions to below 130g/km and, in some cases even lower while also boosting MPG."