"Cars with high fuel consumption already pay more in the tax and duty on the fuel they use, any additional burden is not only bad science but also bad economics (3) and bad news for the election prospects of any party supporting it".

"Measured like-for-like in a calculation that includes all costs from design to vehicle end-of-life decommissioning, a Hummer H3 4x4 is more environmentally friendly than a Toyota Prius (1). Thirdly, the transport sector is already doing more than enough to heed the government's calls for emission reductions, with modern cars "as environmentally friendly as it gets" and the greenest form of family transport available (2). In addition the new energy efficient l.e.d. traffic lights will save two power stations' output of carbon dioxide per year when the network is fully updated."

ABD Environment Spokesman Ben Adams comments: "These proposals are flawed at every step. First, climate change is a natural phenomenon caused by astronomical and geological factors that politicians cannot possibly hope to tackle. Second, even working within the current King Canute form of political science, the list of cars and proposed car tax rates fails to take into account the dust-to-dust energy cost and gets the carbon calculation totally wrong."

The road tax proposals would increase motorists' costs substantially: only fully electric cars would have zero tax, the hybrid Toyota Prius would cost £300 per year, 1200cc cars would be £600, and family cars between £1200 to £1500. A typical Range Rover would cost £1800.

A report by the cross-party Environmental Audit Commission entitled "Reducing Carbon Emissions from Transport" which calls for swingeing increases in road tax and a reduction in the 70mph speed limit, is based on a long list of false premises.