Lib Dems: 4x4 drivers face £2,000 tax

Motorists who drive gas-guzzling cars would pay road tax of £2,000 a year under a shift towards green taxes proposed by the Liberal Democrats.

A policy paper also called for higher tax on air travel, the fastest-growing cause of global warming. It said air passenger travel duty should be replaced by a "pollution charge" on each flight, which could push up fares when planes are not full.

The Liberal Democrats will fight the next general election on a pledge for "fairer, greener but not higher taxes". In July, they will unveil a tax strategy proposing income tax cuts for middle and low earners. Although the well-off would pay more, the party is expected to drop its policy of a 50p tax rate on incomes higher than £100,000 a year.

In the first instalment yesterday, the Liberal Democrats said vehicle excise duty (VED) on the most polluting new cars should rise to £2,000 a year and dismissed Gordon Brown's £45 increase for 4x4 vehicles to £210 as no more than half the cost of a tank of petrol.

"If it is to be effective as a measure to reduce emissions and encourage greener transport, VED will have to be radically redrawn to penalise emissions and reward clean cars," said the paper, The Green Switch.

The £2,000 tax would apply to cars such as the BMW 7 series, Bentley Continental, and 4x4 vehicles such as the Porsche Cayenne and BMW X3. The party said its policy was aimed at "Chelsea tractors" and would not hit farmers. "If people choose to purchase the most polluting cars they must recognise the environmental cost," it said. It added that fuel duty, which has been frozen since 1999, should be allowed to rise in line with inflation.

On air travel, the Liberal Democrats would reward full flights and penalise half-empty ones. The "pollution charge" would be imposed on operators rather than individual passengers.

Vince Cable, the party's Treasury spokesman, said: "People who travel on empty flights might well pay more but people who travel on package flights may well pay less. The basic approach has been endorsed by some of the travel companies such as Thomsons." Chris Huhne, the party's environment spokesman, said: "This is about using tax in a new way to change behaviour. It is not about raising money for the Government."

* Tony Blair faces a rebellion over his plans for a new wave of nuclear power stations. Nine MPs, including the former environment ministers Michael Meacher and Elliot Morley, have signed a Commons motion saying the case had not been made for it.