Gordon Brown is expected to raise taxes substantially on "gas guzzling" cars for Wednesday's budget.

Last year the chancellor's "green budget" gave £35 reductions in car tax to smaller cars but only increased the tax on larger cars by £45, a figure less than the price of a tank of gas and far from being a deterrent to those who can afford to purchase, own and drive large cars, namely 4x4s and "soft-roaders" or "Chelsea tractors", as these road-hogging fashion-accessory-cum-status-symbols have become known.

Some quarters believe that the road tax may double to £400 for inefficient vehicles, although falling well below the mark of £1000 demanded by green groups for the worst polluters. Friends of the Earth, for instance, have called for Gordon Brown to exercise substantial measures if he is to leave a "green legacy" as the chancellor.

He may also offer a few concessions to property owners who are prepared to "go green" with possible stamp duty land tax exemption for the purchasing of "zero-carbon" homes as he first hinted at in his pre-budget report.