Ed Balls , right , has told friends that he does not think that Ed Miliband left , can be Prime Minister . Ed Balls has told friends that Ed Miliband is not up to the job and hasn ’ t ‘ grown ’ into the leadership since taking over in 2010 , a leading Labour-supporting magazine claimed last night . In a profile of the Shadow Chancellor , the New Statesman magazine said Mr Balls does not believe Mr Miliband has the credentials to lead his party . One Labour MP told the magazine that Mr Balls confided in him during Labour ’ s 2010 leadership contest that only he and David Miliband were qualified to take on the leadership , saying : ‘ There are two people who are up this job – one ’ s David Miliband and one ’ s me. ’ The MP said Mr Balls now felt the Labour leader ‘ hadn ’ t grown ’ since his victory , adding he feels ‘ dreadfully sorry ’ about Mr Miliband ’ s failure to connect with voters . The withering verdict will add to the distrust between the two men , who favour different approaches on a string of issues , including the party ’ s approach to business , airport capacity and university tuition fees . Mr Balls is normally described as Mr Miliband ’ s ‘ third choice ’ for the role of Shadow Chancellor , after David Miliband turned it down and Alan Johnson quit . But the profile claims he was in fact the fourth choice , with Mr Balls ’ wife Yvette Cooper also turning down the role . Yesterday he said Mr Miliband had not guaranteed him his job if Labour wins power in May . He said : ‘ I ’ m the Shadow Chancellor and we ’ re working really closely together on our plans , not just for the election but for government . I ’ ve not had that conversation and wouldn ’ t seek to do so . He ’ s the leader ; these are his choices . I wouldn ’ t describe myself as a needy person. ’ Mr Balls also hinted he would back his wife , the shadow home secretary , for the leadership if Labour loses the election . He insisted that he wants Mr Miliband to win , but said of Miss Cooper : ‘ Yvette is a very talented politician and a very special person , and whatever she wants to do in life , I ’ m sure she ’ ll do and she ’ ll have my 100 per cent support. ’ Mr Balls also teased Mr Miliband over his disastrous conference speech last year in which he recounted conversations with a series of people he had met while walking on Hampstead Heath . He said he had been introduced to his future wife by a mutual friend on Hampstead Heath , adding : ‘ We weren ’ t collecting stories for speeches . It was just a walk. ’ The tensions between the two Eds emerged as former business secretary Lord Mandelson predicted Mr Miliband will fail to win a majority in a ‘ stalemate ’ general election and his flagship mansion tax will not raise the tax revenues he claims . Lord Mandelson , picutred , has said that he does not believe Ed Miliband will win enough seats for a majority . The peer also said broadcasters would be wrong to ‘ empty chair ’ David Cameron if he does not agree to three election TV debates – a key demand of Labour figures . His prediction that Labour is not on course for victory was seized on by Tories , who said Mr Miliband planned to ‘ crawl into Downing Street on Alex Salmond ’ s coat-tails ’ . David Cameron said security would be threatened by a ‘ despicable ’ government involving the SNP , which wanted to ‘ break up Britain ’ and scrap the Trident nuclear defence system , and Labour . Lord Mandelson cast doubt on the party ’ s proposed mansion tax , saying of the plan to raise money for the NHS with a levy on expensive homes : ‘ Not in a month of Sundays will it raise the taxation [ that Labour claims ] , everyone knows that. ’ Insisting he would not answer more questions on it , he said : ‘ I don ’ t agree with the policy. ’ Asked if Labour would do better with another leader , the peer replied : ‘ Do you think your product would be better if you changed the wrapping ? It depends what you think people are voting for. ’ In the Commons , Mr Cameron brandished a Labour leaflet from Scotland that he said showed Labour had given up hope of winning a majority and was preparing for a deal with the SNP . It reads : ‘ We need to stop the Tories being the largest party . That ’ s the only way to stop a Tory government . ’
Senior Labour figures now doubt Ed Milliband can win the General Election . Shadow Chancellor Mr Miliband doubts Ed Balls has the leadership skills . The two Labour heavyweights are seen to be drifting apart . Mr Balls has hinted he would back his wife as leader if Labour lose in May . Scroll down for video .