A defiant Ed Miliband has said he will not buckle under the pressure over his leadership as he vowed to take whatever was thrown at him to ensure Labour win the next General Election.

Mr Miliband also encouraged party activists to come out fighting against the Conservatives and Ukip, telling his party it could "take this lot apart".

Rejecting suggestions that he is to blame for Labour's poor poll ratings, he also pledged to tour the country over the next six months persuading voters to back him.

But he was forced to deny suggestions that he was paranoid, following claims that "powerful forces" and "vested interests" wanted to stop him getting into Downing Street.

The speech had been billed as a major statement about why the Labour leader wants to be Prime Minister. But it was dubbed the "10th relaunch" of his four-year long leadership by the Tories.

It follows a poll that suggested only 13 per cent of people think Mr Miliband is ready to be Prime Minister. A separate poll a fortnight ago suggested the party would face almost total wipeout in Scotland if the election was held now.

By one calculation Labour would drop 36 seats to just four, while the SNP would soar from six to more than 50.

Mr Miliband had hinted before the speech at the problems of recent weeks and reports some of his own MPs want him to stand aside. He told members in London yesterday he was "willing to put up with whatever is thrown at me in order to fight for you".

But he also told the party it was its responsibility to keep its "eyes on the prize" of ejecting the Tories from No 10. He set out his vision for a "fairer, more just, more equal Britain".

Mr Miliband also said his party would be talking more about immigration in the run-up to next May's vote.

Immigration and the deficit were the two issues he was ­criticised for leaving out of his party conference speech earlier this year.

Mr Miliband said that public concerns over immigration had to be taken seriously, adding that "it isn't prejudiced to worry" about its effects.

On the deficit, which he forgot to mention during a speech to the Labour conference, he rejected accusations that Labour would be big spenders in power, saying the party would be "wealth creators ... not just wealth distributors".

Miliband said he stood for "basic British values" such as job security, hard work being rewarded, and effective public services. "Big ideas, not the old ideas," he said.

He said the important thing was how to change the country rather than who has their "picture on the wall in Downing Street".

"There's a saying that goes 'what doesn't kill you makes you stronger'," Mr Miliband said. "As Leader of the Opposition, over the last few days I have learned what that really means. You need resilience in this job, you need thick skin, but above all you need belief in what you are doing.

"Not belief based on a longing to have a picture on the wall of Downing Street, not belief driven by a sense of entitlement, not belief driven by the idea that it's somehow Labour's turn, but belief driven by the idea of how we must change the country. That's why I'm in this job, that's why it matters to me, that's what drives me on. And it is through our beliefs that we are going to win the General Election."

Earlier, frontbencher Andy Burnham claimed powerful "vested interests" alarmed by the prospect of a Labour victory were trying to prevent Mr Miliband entering No 10.

l Labour today pledge to bring in tough new penalties to tackle abusive tax avoidance if they win in 2015.