GRADUATED vehicle excise duty to encourage the increased use of 'green' cars will either require colossal investment or be fundamentally flawed on scientific grounds, according to The Parliamentary Office of Science and Technology's paper, 'A Clean Licence? Graduated Vehicle Excise Duty'.

The House of Commons briefing document for MPs has exposed the cracks at the heart of Chancellor of the Exchequer Gordon Brown's plans to introduce graduated VED starting at £100. The Chancellor announced his intention in the March Budget 'to reduce the licence fee for cars with the lowest emissions'.

He said this would initially involve cutting VED for the 'cleanest and smallest cars' by £50 per year, to create an effective VED starting rate of £100, while an official Treasury bulletin declared that less environmentally-friendly cars would pay more than at present. But the Parliamentary Office of Science and Technology has revealed the complexity of the issue, and highlighted the deficiencies in the records held by the Driver and Vehicle Licensing Agency were such a scheme to be introduced.

These records contain only a car's engine size, fuel type and date of registration, insufficient data on which to base a graduated VED, given the motor industry's claims that small does not necessarily mean either clean or green. 'A Clean Licence? Graduated Vehicle Excise Duty' backs up these claims, concluding that any workable attempts to implement a graduated VED would be based on 'proxy' evidence, rather than scientific facts.