Plans by the government to retrospectively increase Vehicle Excise Duty (VED) in a bid to combat climate change has been slammed in a report by the Royal Automobile Club (RAC).
In the Pre-Budget Report chancellor Alistair Darling announced that the tax bands for cars will be rising from seven to 13, starting in April 2009.
From April the cars that are in the additional bands, F to M, will pay an additional £5 a year for the carbon emissions from their cars and from April 2010 the rate will increase by £30 for the most polluting vehicles but may decrease for those that pollute less.
This increase in duty will not only apply to new cars registered but will affect all cars registered since 2001 retrospectively.
The plan has been criticised by the RAC because many people are confused about how to be "greener" and what constitutes as a green car.
The report finds that 77 per cent of motorists would buy a more eco-friendly car if the tax incentives were better. It also found many motorists have little awareness about the causes of climate change and the impact cars have on the environment.
Adrian Tink, RAC Motoring Strategist, said: "It's clear there is a willingness from motorists to be more eco-friendly, but times are tough and despite fuel prices decreasing in recent weeks, looking after the family budget is still their first priority.
"Many motorists also don't know how to be greener, it's a complex issue that even the experts sometimes can't agree on. For now, what motorists can be sure of, is if they concentrate on saving fuel, they'll not only be saving their hard earned money - they'll be doing their bit by cutting emissions too."
The RAC are calling for the government to scrap the current plans to reform the VED as there are more effective ways of encouraging people to buy 'green' cars and that the plans are simply a sticking plaster over the problem.
The addition of fuel efficiency indicators to come as standard with all new cars constitutes another suggestion from the RAC, as does increased 'park and ride' schemes and an overall improvement in public transport.
Drivers also need to be educated about the effect that their cars have on the environment through leaflets and driver re-education for all motorists, not just those currently taking their driving test.
Liberal Democrat transport spokesman Norman Baker said: "The government's ill-conceived road tax changes have left drivers confused and seriously damaged the reputation of green taxation.
"A green tax should be designed to change future behaviour but instead the government intends to penalise drivers for purchases made years ago.
"We need to work towards a far simpler road tax system where VED is abolished and fuel duty reduced, to be replaced by a revenue neutral charge on motorways and trunk roads."
Mr Darling offset the 1.5 per cent cut in VAT by adding 2p onto fuel duty, causing angry protests from lorry drivers who clogged up the roads by driving at a snail's pace. It was received well by environmentalists, however.