Manufacturers are making significant cuts in their vehicles' CO2 emissions, but some countries are reluctant to buy the greenest models, claim the Environmental Transport Association (ETA).

It has commissioned a study, which reveals British motorists languish at sixteenth place in a league table of who buys the most polluting models in Europe.

Portuguese drivers are the greenest when it comes to buying cars with an average CO2 rating of 138g/km.

Meanwhile, the least green motorists are from Latvia with average emissions of 177g/km, while British drivers come sixteenth in the list with average emissions of 158g/km.

"Car makers can build green cars, but they need us to buy them,” explained ETA director Andrew Davis. “The report found that strict new emissions laws are having a strong effect on the availability of cleaner cars, but wealth, motoring taxes, fuel prices and consumer attitudes, which vary wildly from country to country across Europe, have much more of an effect on how clean a car is chosen.

“We need a more sophisticated carrot and stick approach to encouraging people to drive lighter cars if we want to do better in next year's league table."

The EU is striving to cut the CO2 emitted by cars to an average figure of 130 g/km by 2015.