The organisation will start a consultation this week to propose a scheme to charge the cars that make the biggest contribution to global warming, such as 4x4s, high-powered sports cars and some luxury vehicles, the inflated fee.

The highest emitting vehicles currently represent 8 per cent of cars registered in London and if the scheme goes ahead, they would face the higher £25 charge and lose their entitlement to residents' discount.

The charge would only apply to cars within the congestion charging zone which covers parts of Westminster, Kensington and Chelsea. “Londoners are becoming increasingly aware of the need to tackle climate change and this summer's floods were a remainder of the urgency with which we need to reduce CO2 emissions,” said, Mayor of London, Ken Livingstone.

Proposed new charges: Low CO2 emitting cars – 100 per cent discount. Includes cars in VED Bands A and B, emitting less than 120 CO2 per km, which also meets Euro 4 air quality standards Cars in VED Band C, D, E and F, with emissions up to 225g CO2 per km, will pay £8 congestion charge (same as present) High CO2 emitting cars – VED Band G and those emitting above 225g of CO2 per km as well as those registered pre March 2001 with engines larger than 3,000cc, will pay £25 a day.

“The highest CO2 emitting cars can produce twice as much carbon dioxide emissions as the kind of car driven by the average Londoner.” “By proposing these changes to the congestion charging scheme we are encouraging people to take into account the impact on the environment of their choice of car.”

The RMIF has argued that the proposed charge wouldn't necessarily achieve its goal of reducing CO2 in London. “The emissions of most private cars driven in central London fall below the highest proposed emissions-based congestion charge level, so it is questionable if the proposed plan will achieve its aim of further reducing central London traffic levels,” said Alec Murray, non-executive chairman of the RMIF. Murray also said the proposed measures ignored the environmental impact of London's taxis and buses, currently exempt from the charge.