It says new diesel cars emit 95% less soot from the tailpipe than those made 15 years ago, while the average CO² emissions from a new car have been cut by 13.1% since 1997.

The society also says each vehicle made in Britain requires half the energy to make it than it did just five years ago, saving an estimated 700,000 tonnes of CO² a year.

Those figures show how far the industry has come, but there is still more to do.

Vauxhall, at Ellesmere Port, which yesterday said it was scaling back production to cope with falling sales, could benefit from new technology being developed in the US.

Parent company General Motors has, to great fanfare, unveiled new electric car the Chevrolet Volt.

The car, which analysts say will become one of the leading models in the electric car market, would be powered by batteries and an electric motor linked to a petrol engine.

The European version of the car is likely to be built in Ellesmere Port.

But, green measures aside, the car industry will only survive and thrive if general economic conditions improve.

This week, SMMT chief executive Paul Everitt said the industry was facing its most difficult conditions for 17 years.

He has called for the Government to scrap its planned vehicle excise duty increases, which he says are creating growing uncertainty among buyers.

Mr Everitt says the Government must also do all it can to reduce fuel and energy price rises, and should encourage public authorities to renew their vehicle fleets.

He also wants to see measures to encourage motorists to trade up to more fuel-efficient new vehicles, such as a “scrappage incentive scheme” to help people dispose of old vehicles.

He said: “The Chancellor’s pre-Budget report should set out a package of measures to boost demand for new fuel-efficient cars and scrap plans for unfair increases in car tax.”