The Government is expected to come under fire today in a report on plans to raise VED road tax.
Members of the House of Commons Environmental Audit Committee are expected to attack ministers over the retrospective increases in VED due to hit nine million motorists from April next year.
Many cars registered after 2001 face increases in road tax - a move ministers say will encourage motorists to change their cars for less-polluting models.
However, critics argue that the tax rises will do little to alter motorists' behavior and may unfairly penalise poorer drivers who cannot easily change cars.
The committee heard evidence from motoring groups and environmental campaigners.
One committee member told the Daily Telegraph: 'Even those of us who support the idea of green taxes have problems with the way this has been done.
'The Government has made a complete mess of this and jeopardised public trust in the whole principle of green taxation.'
Chancellor of the Exchequer Alistair Darling is already rumoured to be considering modifying his VED road tax rise plans, with the changes widely expected to be announced in the pre-budget report in the autumn.
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