Lucy Powell urges Ed Miliband's Labour critics to 'show us your colours' Campaign vice-chairman Lucy Powell challenges plotters to go public 20 shadow ministers ready to tell Miliband to go to rescue Labour party Tristram Hunt says attempts to bolster leader have been a 'total failure' Caroline Flint admits there are 'jitters' but party must pull together Neil Kinnock says attacks are causing 'damage' and will affect Miliband Alistair Darling says leader still 'needs to show' he is up to the job of PM Warns against Labour's plan for a mansion tax on £2million homes Poll shows 64% of Labour voters think Miliband is not up to being PM Party's four-point lead would double if Mr Miliband stands down Labour MP Simon Danczuk warns the answer isn't to see more of Ed Jewish donors desert Labour after backing motion to recognise Palestine Warning party will have to 'pass the begging bowl' around the unions Ed Miliband's critics in the Labour party were urged to put up or shut up today in a high risk attempt to end the plotting against him. Lucy Powell, the Labour leader's new general election enforcer, ordered plotters to 'show us your colours' or move on, as it emerged as one in five of Mr Miliband's frontbench team is ready to call on him to go. The embattled Labour leader faces a fresh tidal wave of criticism today, with former Chancellor Alistair Darling warning that with just six months until the election Mr Miliband still 'needs to show' he is up to the job of being Prime Minister. In a co-ordinated effort to shore up the Mr Miliband, ex-leader Neil Kinnock warned ousting him would be 'suicide' but shadow cabinet minister Caroline Flint admitted some of her colleagues have 'jitters' about the leadership. Labour leader Ed Miliband, pictured today, is under growing pressure from his own side to up his game, or stand down. Lucy Powell, his new vice-chairman of the party's election campaign, urged his critics to 'show their colours... or move on' Mr Miliband was joined by his wife Justine hours after it emerged up to 20 Labour frontbenchers are now ready to call for him to quit A series of devastating opinion polls released today show growing numbers of voters think he is weak, weird and have no idea what he stands for. The Labour leadership has sought to play down the threat to Mr Miliband, publicly blaming the media for fuelling attacks on him in retaliation for his calls for press regulation. But after a terrible party conference speech, in which he forgot the deficit, a series of botched photo opportunities and the erosion of Labour's poll lead over the Tories, behind the scenes there is a growing sense of dismay about the prospect of Mr Miliband leading the party to defeat. Ms Powell, who Mr Miliband made vice-chairman of the general election campaign in the reshuffle earlier this week, issued a direct challenge to his opponents in the Labour ranks to end the anonymous briefings. 62 shares She told Pienaar's Politics on BBC Radio 5 live: 'Well what I would say to those people is be careful what you wish for because if your analysis is right, that there are people that are concerned about Ed but yet don't want a leadership contest then what they are doing in briefing anonymously and, in my view, cowardly briefing newspapers, they are bringing about the worst of all worlds. They need to decide what their plan is and get on with it either way. She added: 'Either show us your colours and put names to quotes or let's just move on and have a different conversation.' Either show us your colours and put names to quotes or let's just move on and have a different conversation Labour enforcer Lucy Powell Polls show 32 per cent of Labour supporters would be more likely to vote for the party with a new leader. Former Home Secretary Alan Johnson, a former postman who performs strongly in the media, has repeatedly ruled out an attempt to stand as an alternative leader. But if he signalled a change of heart, as many as 20 Labour frontbenchers would be willing to strike against Mr Miliband. A senior figure told The Observer: 'There are 20 frontbenchers who are actively considering what is best to do. They are from all areas of the party, bar the hard left. 'There is a significant number of frontbenchers who are concerned about Ed's leadership - or lack of leadership - and would be ready to support someone who is a viable candidate,' one frontbencher told the newspaper. Alan is that candidate. If Alan indicated he would do it, there would be a massive move. The number of Labour MPs prepared to act has 'reached a critical mass' but they want a coronation rather than a difficult leadership contest, it was claimed. Ex-leader Neil Kinnock warned ousting Mr Miliband would be 'suicide' but shadow cabinet minister Caroline Flint admitted some of her colleagues have 'jitters' about the leadership Caroline Flint, admitted there were doubts in the Labour ranks about Mr Miliband's leadership, but urged the party to hold together ahead of the election next May. The shadow energy secretary told BBC One's Sunday politics: "Some of my colleagues are having jitters and part of that is that we've always said this is not a done deal, this election. This is going to be hard-fought and we said that from 2010 and Ed has been saying it since he was elected our leader. We have to fight for the right to represent the country in Westminster. She insisted that polls still put Labour ahead of the Tories, and the shadow Cabinet had to step up to the plate. Some of my colleagues are having jitters and part of that is that we've always said this is not a done deal, this election Shadow minister Caroline Flint 'We need more of Ed and we need more of the team as well - and they're not mutually exclusive in that regard. With the six months we have got left, yes, Ed will be out there - even more than now, out in the country listening to people but telling them what our offer is. And we need to get behind him to show... this is a team that's going to change the country in 2015. Lord Kinnock, who led Labour to two election defeats, admitted the stories about Mr Miliband's leadership were 'serious' but lacked substance. He told BBC Radio 4's World This Weekend: 'Whilst today's headlines are serious, obviously, they wouldn't be on the front pages of a newspaper otherwise, the so-called threat, and I emphasise "so-called," is certainly not substantial. Not only because all of the so-called sources of the threat are common in their anonymity and cowardice. As far as I can see, their tendency towards political suicide. But because there's no real substance in what they are saying.' He said Mr Miliband would be affected by the attacks. 'You wouldn't be a human being if you weren't sensitive to the kind of criticism that Ed's been getting. Until they identify themselves, it is not possible to say they have substance, even though of course, they are inflicting, at least in the short-term, a degree of damage. A Mail on Sunday poll suggested the party's four-point lead would double if he stepped down in favour of former Mr Johnson or shadow Business Secretary Chuka Umunna. Shadow Education Secretary Tristram Hunt (right) has blasted the desperate attempt of Ed Miliband to revive his flagging personal ratings by 'getting closer to voters' as a 'total failure'. Former chancellor Alistair Darling said Mr Miliband still 'needs to show' he is up to the job of being Prime Minister Former Chancellor Alistair Darling has become the latest senior Labour figure to criticse the party's plan for a mansion tax. Ed Miliband wants to impose a levy on properties worth more than £2million. The money would be used to fund extra cash for the NHS. But Mr Darling is the most senior figure to question the policy. 'I suppose, as a former chancellor, I am not a big fan of new taxes,' he told The Sunday Times. 'The big problem with a tax that came in at £2million is that you could see a lot of people saying, 'My house is worth £1.99million'.' Labour MPs in London have also voiced doubts about the policy. Dame Tessa Jowell said: 'Take one of the many elderly couples living in my constituency in Dulwich, who might have bought a house 30 years ago and are now living on pensions and are asset rich but income poor. No mansion tax should drive them from their homes. Margaret Hodge said: 'I would rather we did it in a slightly different way.' David Lammy said: 'I'm not keen on a mansion tax.' Public opinion has swung dramatically against Mr Miliband in recent weeks. He is now the least popular party leader six months out from a general election for 30 years. The Mail on Sunday revealed shadow education secretary Tristram Hunt's damning assessment of his leader in a private conversation with Labour colleagues. Mr Hunt said: 'I never believed the answer to Labour's problems was to show people more of Ed Miliband. As the row grew, Mr Hunt issued a statement insisting he supported Mr Miliband. He said: 'This is total nonsense and untrue. As I made clear in a full round of media interviews on Friday, Ed Miliband is the right person to lead Labour and the right person to lead Britain. We are focused on the big issues that matter - the cost of living crisis, the NHS and ending the low wage, low skill economy. 'Labour is united under Ed Miliband's leadership.' A YouGov survey for the Sunday Times shows 64 per cent of people think he is not up to the job of prime minister, a dramatic rise from 47 per cent since October 2012. Mr Darling suggested that the Labour leader had failed to prove his credentials for running the country. He told The Sunday Times: 'I think he does, but he needs to show it. I just think that the world may not be as you want it but you get on with it. You have to fight for every vote. People want leadership. Yes, there are difficulties. But you've got to show that you have answers or at least you have an understanding of how you answer the questions. I believe that this election next year is eminently winnable, but to win it we have to be doing that. We have to be out more, we need to be arguing, we need to make much more of the good front-benchers we have, such as Rachel Reeves. Mr Darlings also warned against resorting to a '35 per cent strategy', combining Labour's core vote with disaffected Lib Dems, to scrape into power. My view is you need to aim to win and to win well. If you aim for a number you will come in below it. You cannot win simply by assuming you can hold what you've got. That is silly, even when times are good. We are living in a more volatile political environment than we have done for many, many years. If you aim for a number you will not win but I think my colleagues, from Ed down, are acutely aware of that. Mr Miliband has faced growing criticism for his rambling party conference speech in September, which he delivered without notes and forgot to mention the deficit or immigration. Mr Darling admitted it was a mistake: 'It's a brave man that does a 50-minute speech without a note. I wouldn't try it. You shouldn't knock autocues.' Some of Labour's most senior figures were forced to deny holding secret talks about what to do if Mr Miliband quit as party leader. David Cameron's 'nods and winks' that he might back Britain leaving the European Union is putting the nation's future prosperity in danger, Ed Miliband claims. The Labour leader will use a speech to the CBI tomorrow to warn the UK is being left increasingly isolated and is now on a 'conveyor belt towards exit with no idea how to get off'. He will also pledge not to play 'political games' with Britain's EU membership and insist Labour has a credible and clear plan to secure reforms. He will say: 'There are some people in our country who advocate exit from the EU. There are others who flirt with it, thinking they can do so without consequence. Both are equally dangerous. Giving succour to the argument that the real answer is leaving the EU, or contemplating it, simply drags us closer to exit. And every nod and wink to those who want to leave sends a message to potential investors in our country that we are not open for business. It is a betrayal of our national interest. It is a clear and present danger to our future prosperity. The way to overcome these false solutions is not to pander to them. Not to posture about finding ways of accommodating them. Not to make promises everyone knows you cannot keep. Shadow health secretary Andy Burnham and shadow home secretary Yvette Cooper dismissed reports they intended to present a joint platform in the event of a leadership vacancy. Mr Miliband took to Facebook to insist he will lead Labour into the general election next May, promising to fight 'street by street, house by house'. Aides say they plan to take Mr Miliband across the country to meet more members of the public. But speaking on BBC1's Sunday Politics programme today, Labour MP Simon Danczuk warns this strategy will fail. In a pre-recorded interview, Mr Danczuk said: 'The answer isn't more Ed in the next six months... that approach has already been tried and tested. 'What we need is a team approach, that's the reality of it. 'That's what David Cameron does. He has a team approach and it helps hide some of his weaknesses because he's spreading the load across a number of Cabinet ministers. 'Ed needs to take the same approach because the numbers show us that he's not popular with the electorate. We need to spread the load amongst the shadow cabinet and bring some of them to the fore. The YouGov poll for the Sunday Times found that only 34 per cent of people who voted Labour at the last general election believe Mr Miliband is up to the job of prime minister, compared to 51% a month ago. But Mr Johnson told the paper him becoming Labour leader was a 'definite no-no' and backed Mr Miliband. He said: 'I am not keen to do it. We can win with Ed as leader and I can help him do that. That is why I'm staying on because there is a lot to be done and there is hope for the future if we can regain the trust of the British people. 'I'll help them out. I will do my bit and people will get sick of me on the media in the run-up to the general election. Meanwhile, Labour faces a cash crisis after the loss of major Jewish donors unhappy at Labour backing a motion to recognise the state of Palestine. Critics said the 'toxic' anti-Israel stance meant wealthy members of theJewish community 'just wouldn't touch' the party's fundraising efforts. A former cabinet minister told the Independent on Sunday: 'We will have to pass the begging bowl round to the unions. That would send a bad signal. In return, they [the unions] would demand to call the shots on policy.