Casting himself as the underdog, the Labour leader said he would "relish" the fight over the next year and believes he can "defy the odds" to win the election in 2015. Labour is about four points ahead of the Conservatives in the latest YouGov/Sun poll on 38%, putting Miliband on course to win a narrow overall majority.
However, the party appears to have been unnerved by a series of surveys suggesting its leader is unpopular with the electorate. According to Guardian/ICM research, Miliband has slumped to his lowest ever personal rating, while analysis for Prospect magazine by YouGov suggested six in 10 voters do not think he is up to the job of prime minister.
Damian McBride, Gordon Brown's former spin doctor, said the Labour leader needed more warriors among his advisers if he is to win the election. McBride, who resigned in 2009 over a plot to smear his opponents, said the Labour leader's closest advisers lacked an understanding of what was required to win and would rather be attending a symposium by the French economist Thomas Piketty.
McBride wrote on his blog: "There are many positive things to say about the people managing Ed Miliband's operation and running Labour's campaign. They are well-spoken, well-read, well-connected, and if you stay on their right side, quite genial. You'd feel safe sitting them next to your mum at a wedding.
"But what they are not is fighters … Just like David Cameron, Ed Miliband has been guilty of recruiting his innermost circle of advisers entirely in his own image."
McBride's comments add to a handful of interventions from Labour figures expressing concerns about the party's direction over the last few days.
On BBC's Newsnight programme on Wednesday, Lord Mandelson, a former cabinet minister under Brown and Blair, offered only lukewarm praise for Miliband's leadership. He also suggested the Labour leader's message on business was confusing and called for a better explanation of how the party would bring about growth.
Asked about his support for Miliband, Mandelson said: "In my view, he is the leader we have and therefore the leader I support and somebody who I believe is capable of leading the party to victory."
Alan Johnson, a former home secretary, backed Miliband as leader 100%, but suggested connecting with people was not his greatest strength.
"Maybe [Ed] is not as able to connect as strongly as David can," he told the New Statesman. "It's not his strong point. I can't pretend that, knocking on doors, people come out and they're enthusiastic about Ed."
Meanwhile, Lady Hayman, a former Labour MP who is now a crossbencher following her role as Lord speaker, said Miliband has "never quite managed to be himself and create that identity with the public", despite his strengths.
Miliband said he would listen to advice, but "continuity Labour" was not an option and the party could not carry on in the same vein as the last government.
"I didn't take this job because I thought it would be a walk in the park. I fought for this job because I thought it was important and I thought I had something distinctive to say about how we can change this country, and I believe that more now than I did three and a half years ago," he said. "I relish the next 10 months, I relish the opportunity to fight for my vision for the country."
He made the remarks after setting out Labour's first plans for cuts to the welfare system, ending out-of-work benefits for 18-to-21-year-olds and replacing them with a less costly means-tested payment dependent on training.
The move was welcomed by many Labour MPs as a sign of the party's determination to reform social security, which they will be able to point out to voters on the doorstep. However, it also caused controversy among some on the left.
Unite welcomed Mr Miliband's commitment to training but accused the Labour leader of using "Tory rhetoric of sanction and punishment".
Steve Turner, assistant general secretary, said: "Our young people did not cause the economic crash and shouldn't be made to pay for it. Any idea that they want a life on benefits is risible when all they want is a decent job and a future."
Neal Lawson, chairman of Compass, the left-leaning pressure group, said Labour would never "win on who kicks down hardest on the poorest".
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