Oxford East MP Andrew Smith has backed Labour rebels in their bid to get the Government to overturn its controversial car tax proposals.

Changes made by Chancellor Alistair Darling in the April budget mean owners of the most polluting cars could face a tax rise of as much as £200.

More than 30 Labour backbenchers have signed a House of Commons motion urging ministers to rethink the proposals before the new rates come into force in 2009.

Mr Smith who is currently on holiday in France said: "Introducing something which is effectively a retrospective tax doesn't seem fair to people especially in the current economic climate.

"I hope and expect with the strength of public opinion and the strength of backbencher opinion that Alistair Darling will have to have a rethink on his plans."