London Mayor Boris Johnson is considering a plan to charge owners of many diesel cars a supplementary £10 to drive into central London on top of the existing Congestion Charge, pushing the price past the £20 mark to visit the capital.
According to a report by The Times, the Mayor will tonight announce his plans as part of a push to slash air pollution in the capital.
Other cities across the UK could follow by introducing their own versions of London's Low Emissions Zone (LEZ) to meet increasingly stringent clean air rules set by the European Commission.
Under the Mayor's plan – which could be introduced in 2020 – the Euro 6 compliant diesel engines that are currently being rolled out would be exempt from the extra charge, but some older and less-efficient petrol-fuelled cars could be penalised.
London is under severe pressure from Europe policy-makers due to its above-average levels of air pollution, and the toxins produced by diesel vehicles are cited as a key contributor to respiratory diseases. The Congestion Charge currently costs £11.50 per day for vehicles which produce more than 75g/km of CO2.