More than 30,000 Shropshire motorists will see their car tax bills rise under the Government’s controversial plans to clamp down on pollution, it was revealed today.

And hard-pressed drivers face a double whammy after the AA revealed people were already paying too much for their fuel – with a big cut in the cost of crude oil not being passed on to drivers.

New figures show that the price of oil has fallen by a quarter over the last two months, but the cost of fuel at the pumps has remained stable.

Meanwhile the Government’s “retrospective” car tax hike on the most polluting cars, due to come into effect next year, will classify all vehicles purchased since 2001 on the basis of their carbon emissions – and push more bills up.

Today, a car that produces between 186 and 225g/km of CO2, such as a Land Rover Freelander diesel 2.2 TD4 GS – one of Britain’s five most popular cars – or a Peugeot 407 Saloon 2.0 Auto, would incur an annual tax of £210.

The owner of a car, such as a Land Rover Sport Auto 3.6, which emits more than 225g/km of CO2 is taxed at £400.

Under the proposals, drivers of such cars registered after March 2001 – of which there are 30,704 in the county – would see their tax rise by between £15 and £90 in 2009.

And the net is much wider because the latest figures from the Department for Transport only detail the number of licensed cars by carbon emissions in the current top two tax bands.

A Treasury spokesman said the new plans would encourage people to use more environmentally friendly cars as well as save 1.3m tonnes of CO2 by 2020.

But the move has been criticised by motoring organisations and MPs who have slammed the retrospective tax as “unfair” and “unacceptable”.

Edmund King, president of the AA, said: “This is not sending out a green signal but a mean signal and is penalising many families who cannot afford to change their car.”

With the price of oil coming down, he criticised fuel companies for being “too slow” in passing on the full reduction to motorists.

By Sunita Patel