MOTORISTS are facing a fresh squeeze from Alistair Darling, the chancellor, with a one-off £2,000 tax on 4x4s and the most polluting cars, a leaked Treasury paper has revealed.

The new “purchase tax” would have to be paid when a luxury car, such as a Range Rover or top-of-the-range BMW, is bought at the showroom. In subsequent years owners would pay the top rate for their road tax disc, which is also set for big rises under the confidential plans.

The document says that although the changes will be “presentationally difficult” for ministers, the measures will “strengthen the environmental signal” and boost the Treasury coffers.

People who opt for the cleanest models, such as the G-Wiz electric or Smart cars, will get a cash boost by being able to claim a £2,000 rebate off the purchase price of the vehicle.

The Treasury paper has been drawn up by officials ahead of next month’s prebudget report, with the changes likely to be implemented in Darling’s first budget in the spring.

The measures will be greeted with alarm by some motorists, who were already bracing themselves for rises in vehicle excise duty (VED) next year.

The Conservatives yesterday accused the government of “hypocrisy” because Treasury ministers have attacked Tory proposals to introduce green taxes for motorists. Last week Andy Burnham, the Treasury chief secretary, criticised the Tories for seeking to raise green taxes to “eyewatering” levels. They also included a “showroom tax”.

The 15-page paper, headlined Options for PBR 07 / Budget 08 and circulated in Whitehall this month, makes clear that Darling plans to make big rises in road tax, either through the one-off purchase tax or raising the levy in various bands of VED.

“Increasing rates at the top end protects revenue and strengthens the environmental signal,” the report states. “Reducing rates at lower end strengthens environmental signal.” However, the report goes on to admit that “under any option emission reductions are small”.

The paper acknowledges that if introducing the higher taxes is successful in making people give up “gas-guzzling” cars it will lead to a loss of about £180m in fuel revenue in five years’ time.

One option is to introduce the £2,000 purchase tax for a newly created top band for vehicles with emission levels of more than 254g of CO2 per km, such as a Range Rover 4.4L V8. The equivalent rebate would be paid to the lowest band, consisting of cars such as the Smart diesel with emissions of less than 100g/km.

Another option outlined in the report would lead to big one-off hikes for all new cars, before reverting to “normal” levels of road tax - although the report shows that the Treasury plans to put these up in the coming years to still higher levels than those already announced.

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