Gordon Brown is under increasing pressure to reverse proposed changes to the car tax system, following a stormy exchange with Tory leader David Cameron in Parliament yesterday.
Cameron said to Brown: 'Don't you understand that if you don't get rid of it [the tax increases], they will get rid of you.'
Brown responded by saying that 24 out of the top 30 models of cars would incur the same road tax bill or lower. But Cameron in turn said, 'What you are doing is treating the Ford Focus as one model - in fact there are 40 models of Ford Focus.
'When are you going to stop using such dodgy statistics to back up your figures?'
The Prime Minister said Cameron sounded like a used-car salesman.
What the argument is about
When the tax changes were first announced in the Budget, it was thought that buyers of high-emitting new cars would be worst hit, but it subsequently came to light that cars registered between March 2001 and March 2006 could also be hit by the tax increases.
From next year, these older cars could face a 200 increase in road tax - a move which some Labour back-benchers and Tories say will hit poorer drivers hardest.
The road tax increases are designed to encourage car buyers into less-polluting cars, and Brown hit back attacking the Tories' green credentials.
'When is the Conservative Party going to be honest when it says it supports green taxes and then it runs away from every one of them?'
• Bikers protesting against high fuel prices are causing delays in and around Manchester today. Around 500 bikers are taking part in a slow protest, riding into the city centre.