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The Liberal Democrats have called for petrol and diesel car engines to be banned by 2040 under radical proposals to tackle Britain’s carbon output and control climate change.

Environmental spokesman Chris Huhne was setting out plans to make Britain carbon neutral by 2050 at the party’s annual conference.

Huhne indicated that petrol are diesel vehicles were being made obsolete by advances in hybrid vehicles and hydrogen fuel cell technology.

During his speech, Mr Huhne commented: “The EU Commission wants to set limits on car emissions, but it should state clearly that no car can be sold in the EU if it still belches carbon by 2040…We have to get tough with car-makers about emissions.”

And drivers and 4x4s would also be in the sights of a Lib Dem government, with plans to increase road tax on such vehicles to £2000 per annum, while smaller city cars would pay no road tax.

Huhne also outlined plans to charge lorries to use UK roads in an effort to double rail investment and move freight onto railways and to levy a £10 charge on domestic flights.

"We should be working towards a carbon-neutral Britain by 2050. We should be working towards the elimination of petrol-driven motor cars," said party leader Sir Menzies Campbell.