Buyers, manufacturers and retailers of high-emission cars in Britain are to be hit by a reform of the vehicle excise duty, which will include the imposition of a new first-year rate of as much as £950 per car.

The regime announced on Wednesday will take effect in 2009 and apply to the “highest-polluting cars”, Alistair Darling, the chancellor, said. Cars emitting more than 255g of carbon dioxide per km would be subject to the highest rate.