Something has happened to Ed Miliband in the past week. It is as if, in that what-doesn’t-kill-you-makes-you-stronger way, Michael Fallon’s accusation that the Labour leader would stab the country in the back, together with a Daily Mail front page of his former girlfriends in which he was portrayed as a “cad”, has drawn Miliband out of himself. In his first newspaper interview since these twin incidents, Miliband seems unburdened and, it must be said, for someone so often criticised for looking awkward, comfortable in his own skin.

The last time I interviewed the Labour leader, on a train to Bristol last year, he was ambushed by a hen party who were all dressed up as Ed Balls. This time, on the Edinburgh to York train, there are close protection officers in the row of seats behind him. There are still three and a half weeks of this campaign to run, with a risky opposition leaders’ debate this week, but it is now not hard to imagine him as prime minister.

In pictures: Experts' predictions for the General Election - 11/04/15 Show all 10 1 /10 In pictures: Experts' predictions for the General Election - 11/04/15 In pictures: Experts' predictions for the General Election - 11/04/15 Andrew Hawkins (ComRes) “Events last week have reinforced my prediction that the Tories will be the largest party. Ukip’s slow puncture may help the Tories most, and Nicola Sturgeon may well fulfil her wish to keep David Cameron in No 10 by reducing Labour’s Scottish MPs to numbers that could fit in a stretch limo.” Andrew Hawkins In pictures: Experts' predictions for the General Election - 11/04/15 Joe Twyman (YouGov) “The national picture remains largely unchanged, but YouGov’s Scotland polling shows the SNP at an all-time high. Only 44 per cent of Labour supporters felt Jim Murphy performed best in the first Scottish leaders’ debate.” In pictures: Experts' predictions for the General Election - 11/04/15 Ben Page (Ipsos MORI) “I need to see a more decisive shift in the polls to think that Labour have definitely moved ahead of the Conservatives. There has been more good news for Labour than the Conservatives, with Ed Miliband’s personal ratings improving. Still, a hung parliament remains the most likely option.” In pictures: Experts' predictions for the General Election - 11/04/15 Rick Nye (Populus) “No change.” In pictures: Experts' predictions for the General Election - 11/04/15 Nick Moon (GfK) “I haven’t changed my broad view that the Tories will be the largest party, but Labour is likely to form a minority government. Last week’s projection (Con 280, Lab 273) looks pretty likely to me. The risk for Labour was that, as decision time looms, voters might take ahold of nurse, but that may be mitigated by Miliband’s showing in the debates.” In pictures: Experts' predictions for the General Election - 11/04/15 Damian Lyons Lowe (Survation) “Unchanged, except for an SNP uptick at Labour’s expense. The SNP’s surge in Survation’s polling continues unabated. Nicola Sturgeon scored well in our debate polling.” In pictures: Experts' predictions for the General Election - 11/04/15 Michelle Harrison (TNS) “Despite all the sound, fury and bluster, there has been no game-changer. If anything, it’s become even tougher for the major parties, with signs of a softening in Conservative support and continued evidence that the SNP will inflict major damage on Labour.” In pictures: Experts' predictions for the General Election - 11/04/15 James Endersby (Opinium Research) “Our latest polling figures, published today, show movement back towards the Conservatives (a two-point Tory lead). My prediction last week of a shaky sway back in favour of the Tories on election day holds fast; and with a hung parliament, who on earth knows who’ll be able to form a government?” In pictures: Experts' predictions for the General Election - 11/04/15 Martin Boon (ICM) “At the equivalent point before the 2010 election, our poll suggested 37 per cent for the Tories and 31 per cent for Labour, which more or less nailed the actual result. I think that campaigns mostly reinforce perceptions rather than change minds.” In pictures: Experts' predictions for the General Election - 11/04/15 Lord Ashcroft (Lord Ashcroft Polls) He refuses to make predictions. “My polls are snapshots, not predictions.” Rex

While Miliband is cautious – he has just come from Scotland, after all, where Labour is in serious trouble, and keeps saying the election is “very tight” – he seems almost relieved that the Conservative gloves have come off and Fallon has gone for him. Why? “I suppose we always knew it was coming, didn’t we? We always knew this was going to happen; there was a very big sense they were going to do that, you could sort of see this [Lynton] Crosby-style campaign.”

The Fallon attack, in which the Defence Secretary also accused Miliband of stabbing his brother David in the back, backfired, with even a Telegraph leader calling it “ill-judged”. Miliband adds: “Critically it’s not going to work for them, it looks far too desperate. But they haven’t really got much to say. I was really struck, standing in the debate with Cameron, that his opening statement was backward-looking… it sometimes looks as though he doesn’t know why he’s there.”

Even though the Mail front page seems to have had the inadvertent effect of helping to de-geek Miliband and turning him into an unlikely Lothario, why does he think that newspaper and others go for him? “Because they can. I’m not at all bothered about attacks on me, but I don’t think it’s very nice for the other people who are not in the public eye. Just because they’ve gone out with me, they shouldn’t suddenly find themselves splashed across the front of the Mail.”

Ed Miliband kicks off manifesto week with Labour's launch in Manchester (PA)

I wonder, then, was the “humanising” strategy – including his wife Justine doing television and newspaper interviews, allowing cameras into his home and his kitchen, the Absolute Radio tell-all – a mistake? Given that it was an interview his wife gave to the Mirror, in which she mentioned she had been “furious” to find out, at a dinner party in 2004, that the man she had just met was secretly dating the hostess, is it perhaps better for politicians to focus on policies? Miliband laughs at the obvious irony: “That’s never normally been the accusation. Too much Absolute Radio? No.”

So no regrets at the way the campaign has gone? “Not at all, no. On the Justine thing, she is spending quite a lot of time in this campaign going round the country, talking to activists, going to key seats. I think it’s good that she is doing media stuff.

“The Conservatives thought they could run a nasty campaign against me, and for some reason they thought that that would do the trick. Instead, what the campaign has done is give me the opportunity to show the real me, not the caricature. And that’s why doing the TV debates are important.” You can forgive Miliband for seeming impassioned at this phrase “the real me, not the caricature”, given all the Wallace and Gromit portrayals, the repeated use of the bacon sandwich picture, the largely hostile press. With the television debates it’s just him and the voters – no prism, no caricature.

But his real opponent, of course, is the Prime Minister. How much will the next four weeks be about the characters of Miliband and Cameron? He says: “I am proud to make it about leadership, I am happy to make this about the kind of leadership I offer because I’ve got big ideas to change the country. The British people want somebody who’s got principles and can stand up to the powerful on their behalf. They want somebody who cares about decency. These are important qualities.”

Depending on which media outlet you believe, Ed Miliband has either already lost the general election, or very much hasn't (PA)

One of these ideas is his £7.5bn war on tax avoidance, which he describes as a major change to the way the country is run, on the scale of how Attlee, Wilson and Blair, Labour’s three most successful prime ministers, defined their eras. This is a bold comparison, yet when I try to get Miliband to talk about life post-election, he refuses to discuss anything like measuring curtains at Downing Street. Likewise, his aides downplay the way the polls are shifting, very slightly, in Labour’s favour, because there is still a long way to go. Miliband reveals that he and Justine have not talked to their two young sons, Daniel and Sam, about how life might change in May: “Mainly because we’re not presumptive people… Justine is very good on this: she’s sort of… one thing at a time, cross that bridge when we come to it. That’s totally the right way.

“It’s tough for them because I don’t see very much of them. They obviously know the election is going on, and we’ve talked to them about it and they’re quite enthusiastic about delivering leaflets. But I think they’ve got other things on their mind, like The Octonauts.” He and Justine have read them The Election by Eleanor Levenson, a picture book in which two families campaign for the spotty party and the stripy party, to their sons: “They asked us are we the spotty party or the stripy party, I said we’re the red party. The red team.”

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