Gas-guzzling four-wheel drive cars would be charged a double congestion charge under the Liberal Democrats.

The idea would mean hefty road bills for drivers of Sports Utility Vehicles (SUVs) in Putney and Wandsworth Town, who are among the most enthusiastic buyers of the controversial vehicles.

Environmentalists condemn the 4x4s for their high fuel consumption and now the Lib Dems have said they would penalise a specific list of 68 models.

Tooting Liberal Democrat spokeswoman Stephanie Dearden said: "SUVs are great in rural areas but in city centres they are a danger to pedestrians, a potential hazard to other road users, can cause more damage than any other type of car and take up more roadspace, so increasing congestion.

"The Mayor has dodged and weaved on this issue but it is clear from our research that it is possible to identify Sports Utility Vehicles and charge them double for entering the congestion charge zone."

Those footing higher bills would include motorists behind the wheels of the BMW X5 series, Landrover Discoveries, Ford Explorers, Vauxhall Fronteras and Suzuki Grand Vitaras.

Jeep Cherokees, Toyota Landcruisers and Volvo XC90s would also be told to cough up extra cash for coughing out extra fumes.