Livingstone will put £5 toll on motorists in London, says Blair

Tony Blair launched his fiercest attack to date on Ken Livingstone yesterday, claiming that he would charge motorists £5 a day to drive into London and land the city with "a millstone of debt" on the Tube.

In a fresh attempt to undermine Mr Livingstone's campaign for mayor of London, the Prime Minister also criticised the MP's alliance with the Greens in next month's elections and claimed he was a "show business candidate".

Mr Blair stepped up his assault as he appeared alongside Frank Dobson, the official Labour candidate, to warn voters that they would be stuck with Mr Livingstone for four years if he won the mayoralty.

The Prime Minister spoke of his frustration that, despite the power of the mayor's job, the contest had become a "policy-free zone" dominated by the former Greater London Council leader's "chatshow" politics. But he refused to accept that Mr Dobson would not win on 4 May. "I believe that the closer we get to polling day, the more people will turn to Frank. What's changed in the atmosphere of this campaign is there's an understanding that this is a policy job and a four-year job," he said.

In a strong defence of the Government's public-private partnership (PPP) for the Tube, Mr Blair claimed Mr Livingstone's rival scheme for bonds would lead to "delay and massive debt". Attacking the "Red-Green alliance" between the former Labour MP and the Greens, he claimed few people were aware of what the environmentalists' policies were.

The Prime Minister also attacked Steven Norris for his support for full-scale privatisation of the Underground and his recent claim that he was not standing for the Tory party.

Mr Dobson also stepped up the rhetoric, claiming Mr Livingstone's comments on drugs, his comparison of business to Hitler and his support for City riots proved his unfitness for mayor. He added that Mr Norris was a "serial privatiser, faithful to the end" to the idea of selling off the whole Tube network.

Mr Livingstone hit back, claiming the PPP Tube modernisation could cost £100m in consultants' fees alone. "The PPP consultants' gravy train shows once again how vital it is that the future of the Underground should be decided by London," he said.

Mr Norris said Mr Blair's intervention revealed Labour was clearly "rattled" by opinion polls showing him running second to Mr Livingstone. "They recognise that this is now a two-horse race between me and Ken Livingstone," Mr Norris said.