Land Rover Jaguar yesterday pledged lower C02 emissions from its vehicles to exempt them from London's increased congestion charge - as luxury car company Porsche prepared a legal challenge against the capital's policy.
Porsche said it believed the move to increase the London congestion charge from £8 to £25 for the highest-polluting vehicles was "unfair" and it was applying for judicial review of the decision.
The new charging regime, to begin on October 27, will see the £25 charge apply to vehicles emitting more than 225 grams of carbon dioxide per kilometre, as well as those registered before March 2001 which have engines larger than 3,000cc.
Those vehicles getting a 100 per cent discount will emit less than 120g/km.
Of cars currently being driven in the congestion charging zone, 17 per cent would be liable for the £25 charge and just two per cent for the total discount.
Among the models which will now be subject to the £25 charge is the Land Rover Discovery 3, which emits 270g/km.
But spokesman Don Hume said the company had invested £700 million in environmental technologies and the Freelander II and all diesel Jaguars would have emissions reduced so they were not in Band G which would incur the higher charge. The concept Land Rover LRX will be at 120g/km which will give it a 100 per cent exemption.
The Porsche action could have major implications for luxury and top end models and Mr Hume said: "We are certainly taking an interest in what Porsche are doing and will watch to see how they fare at this stage.
"From a Land Rover perspective, we have made a stand about policies on CO2 and congestion and recognise the importance of reducing emissions."
Porsche said the increased charge would hit businesses as well as drivers and it would be writing to Mr Livingstone this week and that he would then have 14 days to respond to the company. Andy Goss, managing director of Porsche Cars GB, said: "A massive congestion charge increase is quite simply unjust. Thousands of car owners driving a huge range of cars will be hit by a disproportionate tax which is clear will have a very limited effect on CO2 emissions.
"If the Mayor fails to respond to Porsche's letter or refuses to reconsider his plans, Porsche intends formally to submit its application for judicial review at the Royal Courts of Justice."
Mr Goss added: "Not only is this rise completely unfair to many drivers, but it will also damage London based-businesses of all sizes, and successful people from across the world will start to think twice about basing themselves here if they think they are going to be used as cash cows for City Hall (Mr Livingstone's headquarters).
"The proposed increase will be bad for London as a whole and will send out the signal that it is not serious about establishing itself as the best place in the world to do business."
AA president Edmund King also criticised Mr Livingstone's decision, saying it represented a change from a congestion charge to an emissions charge "almost overnight".
"Larger families with some people carriers or estate cars will also be hit. These families in London tend to do lower mileage, use public transport more and keep their vehicles longer. The (car tax) band G people carrier in London will often produce far less CO2 than a smaller vehicle elsewhere due to lower mileage," said Mr King.
"Many ordinary families in London will be hit by these extortionate charges as they will be unable to replace their vehicles by October.
"The Government should take a lead on how to reduce the environmental impact of vehicles rather than having different local authorities cashing in."
However, Blake Ludwig, campaigns director for the Alliance Against Urban 4x4s, said: "We know from the support for our campaign, and our own surveys, that charging the most polluting cars a higher congestion charge is already very popular with the public."