Cameron and Clegg are hailed the winners of final leaders’ debate

(BBC/ PA)

David Cameron emerged as the winner from the party leaders' final television debate last night despite a final "trust me" plea by Gordon Brown on the economy.

Three instant polls gave victory in the debate to the Tory leader but suggested that the Liberal Democrats are still big players in the election race by putting Nick Clegg in second place. A fourth poll scored last night's debate as a draw between Mr Cameron and Mr Clegg. The Liberal Democrats declared they were now in a "two-horse race" with the Tories.

A ComRes survey for ITV News found that the Tory leader was seen as the winner by 35 per cent, with Mr Clegg on 33 per cent and Mr Brown on 26 per cent.

A YouGov poll for The Sun put Mr Cameron on 41 per cent, Mr Clegg second on 32 per cent and Mr Brown on 25 per cent. Angus Reid scored the Tory leader on 37 per cent, the Liberal Democrat leader 30 per cent and the Prime Minister 23 per cent.

However, a Populus survey for The Times put Mr Cameron and Mr Clegg neck and neck on 38 per cent, with Mr Brown trailing on 25 per cent.

Tony Blair will today be drafted in to bolster Labour's flagging drive for votes, campaigning in marginal constituencies in the South-east of England. The former Prime Minister, who spoke in his former Sedgefield constituency at the start of the campaign almost a month ago, will also travel to the North-west next week.

In Mr Cameron's closing statement, he said Labour offered "more of the same," and the Liberal Democrats only uncertainty. "There will be difficult decisions, but I want to lead us through these to better times," he said.

Mr Brown appeared to concede that he was heading for defeat in next Thursday's election. "I know if things stay as they are David Cameron, perhaps supported by Nick Clegg, will be in office," he said.

He acknowledged his personal failings but argued that his record meant it was too risky to ditch him at a time of fragile economic recovery.

Mr Brown tried to move on from the self-inflicted disaster on the eve of the debate – his unguarded description of pensioner Gillian Duffy as "bigoted" in Rochdale. He said: "There's a lot to this job. And as you saw yesterday, I do not get all of it right. But I do know how to run the economy in the good times and in the bad."

He told voters: "It's not my future that matters, it's your future that's on the ballot paper next Thursday and I am the one to fight for your future."

Urging the public not to take a gamble on Mr Cameron or Mr Clegg, Mr Brown declared: "Things are too important to be left to risky policies under these two people. They aren't ready for government because they have not thought through their policies."

According to the ComRes survey of 2,300 people who watched last night's debate, Mr Brown's gaffe has cost Labour support. Seven per cent of people who were planning to vote Labour said they would not, and another 8 per cent who had intended to back the party were now undecided. Another 24 per cent would stick with Labour and 61 per cent were not planning to support the party or were undecided.

In last night's debate, broadcast live on BBC1, Mr Brown looked tired but came out fighting. He drew blood by repeatedly attacking what he called Mr Cameron's "unfair and immoral" plan to raise the threshold for inheritance tax to £1m, or £2m for couples, which would prioritise the richest people while cutting child tax credits for middle class families. Mr Brown also condemned the Liberal Democrats for wanting to cut back tax credits – and took a swipe at speculation that Mr Clegg's party could support the Tories in a hung parliament. Accusing the two other parties of having a "coalition for cuts", he said: "I will never form an alliance with a Conservative Party that cuts tax credits."

Mr Cameron sidestepped the criticism of his inheritance tax policy, but accused Mr Brown of frightening people by claiming the Tories would withdraw child tax credits from low-income families when their plans would only affect those with an income of £50,000 a year.

The Tory leader, who accused Mr Brown of "having nothing positive to say" after 13 years of Labour rule, insisted that tax credits "would stay" under a Tory government. "Gordon Brown has got to stop misleading families in this country like he's been misleading older people and cancer patients as well."

Mr Clegg concluded by saying: "Don't let anybody scare you from following your instincts next week...I can't guarantee that all the problems you face will be solved overnight. But I can guarantee that I will work tirelessly to deliver greater fairness for you."

The debate brought angry clashes on immigration after the issue was propelled up the election agenda by the incident in Rochdale, when Mrs Duffy asked Mr Brown about migration from Eastern Europe.

All three leaders denied the suggestion from a questioner that politicians were out of touch with public concerns over immigration.

Mr Brown said he went into politics to fight for jobs, adding that Labour moves to limit immigration were aimed at creating jobs for British workers. "I want to see a situation where we increase the number of jobs that people in Britain can take, as we lower the number of people coming into the country," he said.

Mr Cameron and Mr Clegg clashed repeatedly over Liberal Democrat proposals to give an amnesty to illegal immigrants who had been in Britain for 10 years.

The Tory leader claimed: "It just doesn't make sense – it would be a mistake that would make a bad situation after 13 years of Labour worse." But Mr Clegg retorted that he was trying to "deal with the world as it is" by getting illegal workers "out of the shadows", telling his rivals: "Get real."

The Liberal Democrat leader ridiculed Tory plans to impose a cap on immigration, challenging Mr Cameron to name the figure at which it would be set and saying it ignored the fact that 80 per cent of immigration came from within the EU and could not be repeated.

During the debate, Mr Clegg appeared rather marginalised at times when the Tory and Labour leaders clashed. He attacked the "political point-scoring" and "old politics" of the two other parties.

"Of course, they'll [Mr Brown and Mr Cameron] tell you tonight that these things can't be done. But I think we've got to do things differently – to deliver the fairness, the prosperity, the jobs which you and your families deserve."

The spending cuts and tax rises after the election will be so severe that the party which implements them will be thrown out of power for a generation, the Governor of the Bank of England has warned.

Mervyn King is reported to have made his prediction about the public anger the deep cuts would provoke in a meeting with American economist David Hale, who told Australia's ABC TV network: "I saw the Governor of the Bank of England last week when I was in London and he told me whoever wins this election will be out of power for a whole generation because of how tough the fiscal austerity will have to be."