In a report for the Government, published alongside the Budget, she argued that labels which currently show the running cost of owning a car for a year should show costs for a decade or longer.
The scheme would also extend to include used cars registered from March 2001. Professor King recommended showroom labelling should include information comparing CO2 emissions and fuel economy with the class average or best-in-class vehicle.
It should also show data on the fuel cost savings resulting from choosing a more efficient vehicle. Professor King believes such information would shock buyers into opting for greener choices.
For example, a 4.2-litre petrol V8 Range Rover, driven 12,000 miles a year for 10 years, would cost more than £35,000 in petrol and vehicle excise duty while a 1.6-litre HDi diesel Peugeot 307 would cost around £11,000.
“Simply choosing the lowest emissions vehicle in a given class can reduce a driver’s CO2 emissions by up to a quarter,” King said.
However motor retail analysts claimed the plan would miss the mark, as buyers typically change cars at three to five years.
The report also suggested forming an advisory group which will ensure all vehicle advertising shows information on CO2 emissions and fuel economy in a more prominent and consistent form.
King’s other recommendations include implementing a 130g/km CO2 emissions target based on the sales weighted average emissions of new cars. For 2020, this should be 100g/km, she said.