Land Rover has added its condemnation of the proposed changes to London’s congestion charge, which will see the vast majority of its vehicles liable for the new £25 a day levy.

While the manufacturer is notplanning to take the mayor to court, as Porsche says it will do to force him to change his mind, it has said the proposed changes need revising.

Land Rover said it is investing millions on new technologies and has already developed the first micro-hybrid Freelander, which will go on sale early next year.

It also recently showed the LRX Concept car, a diesel hybrid capable of emissions below 120g/km CO2 - and so entitled to a 100% discount under the mayor's changes.

"We have real concerns about the mayor’s changes to the London congestion charge, which we believe will have immediate costs for our business, but doubtful benefits from an environmental perspective,” said Land Rover's managing director, Phil Popham.

"Punitive measures like the increase in the congestion charge only make it harder for us to invest in technologies that would make a real difference in cutting CO2 levels."

Last year, Land Rover commissioned an independent report by the Centre for Economics and Business Research, who carried out an assessment of the proposals.

It found that it was doubtful that the mayor’s proposals will have any benefits in terms of reducing pollution or congestion.

However, the mayor's office has said Ken Livingstone is committed to implementing the changes, which will come into force in October.

In the meantime, Mr Livingstone must win the mayoral election on May 1. If he fails to win, it is doubtful the changes will be implemented in their current form.