The total amount of carbon emitted by cars in the UK in 2003 was the same as in 1993, despite a 25% increase in the number of cars on the road.

In 1993, there were 24 million cars on the road in the UK emitting 19.8 million tonnes of carbon. In 2003 the number of cars had grown to 30 million, yet the total amount of carbon was the same, according to Department for Transport statistics.

Chris Macgowan, Society of Motor Manufacturers and Traders chief executive, said: “There are 850,000 people working in the UK motor industry and we are all concerned about the impact our industry has on the environment. We recognise that we are part of the problem and also the solution.

“This is why we have invested so heavily in research and development of new technologies that have helped us to create cleaner vehicles.”

In 1997, 77% of new cars would have been in the top three vehicle excise duty bands: vehicles emitting more than 166 g/km of CO2. In eight years, that figure has nearly halved to 41%. In the lowest three bands, there are now four and a half times more new cars: 34.1%, up from 7.8% in 1997.