Blair fears 800,000 voters in marginals will stay at home

Tony Blair was dogged by doubts surrounding his decision to invade Iraq throughout the last day of election campaigning.

At his final campaign press conference, the Prime Minister warned wavering voters not to act against him over the war, saying: "If people make a protest vote, they could end up with a Conservative government."

Labour strategists fear the party's lead in the polls could be overturned in the marginals, where abstentions among 800,0000 disgruntled voters over the war could hold the key.

The press conference was held in Finchley, Margaret Thatcher's former seat, to emphasise the importance of turnout by Labour voters in marginals.

After a final hectic day of campaigning, it is understood that Mr Blair is planning to hold a meeting with his most trusted ministers at his constituency home in Sedgefield to plan ­ assuming victory ­ the cabinet reshuffle expected tomorrow and priorities for the Queen's Speech that will set out the new legislative programme.

The Deputy Prime Minister, John Prescott, who played a key role in bringing Mr Blair and Gordon Brown together for the campaign, gave a clear signal at yesterday's press conference that he does not want to move from his Whitehall post. He jokingly told journalists he wanted to carry on for another 10 years. Mr Brown was assured by Mr Blair at the outset to the campaign he would not be moved, despite reports that the Labour leader wanted to ditch the Chancellor.

Tory strategists said the Labour lead over the Conservatives took off from the moment that Mr Brown was brought to the campaign's heart. Alan Milburn, the campaign strategist, who was given Mr Brown's election role by Mr Blair, was sitting in the back row for the press conference.

The campaign clearly showed that the youthful popularity of Mr Blair, which helped Labour win two elections, has worn off to the point where he was seen as an electoral liability for a third term. Mr Blair, who has announced his decision to step down after serving a full term, will be closely watching the size of the majority to see how long he can stay on.

Margaret Beckett, the Environment Secretary, another minister who has been sidelined in the campaign, but who could survive the reshuffle, defended Mr Blair's leadership at the press conference against claims that he had lied over Iraq. "People are not just electing candidates," she said. "They are electing a prime minister. I believe Tony Blair has leadership qualities that Michael Howard lacks. Tony Blair doesn't duck issues."

Labour strategists admitted Mr Howard's low popularity with the voters had worked in their favour. "The trust thing has been misrepresented as a vote-loser for Labour," said one. "We had a simple answer, which was to say to Labour voters, who do you trust, Blair or Howard? That is a no-brainer for Labour. Howard has been Labour's secret weapon."

The Tories beat Labour in the early rounds of the campaign, finding Labour slow to react to policy initiatives such as discounts on council tax. But the Tory plans unravelled and they were unable fully to exploit the Iraq issue, after Mr Howard said he would have supported regime change, even though it was illegal.

Working in tandem with Mr Brown, Mr Blair kept the focus on the economy. "People were voting on the economy and public services," said a Labour insider. "The attacks on Blair actually succeeded in driving Blair and Brown together."