A year ago he was preparing for government. Now he’s campaigning on the streets of Doncaster and waiting in for the Ocado order. So what will the former Labour leader do next – and what does he make of his successor?

Ed Miliband interview: 'The thing that's important to me is that the fight goes on'

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There is a cosy hush in the sunlit living room of Ed Miliband’s north London townhouse. Warm spring light is flooding through the bay window; a magnolia tree blooms in the front garden outside. Aside from the ring on the doorbell that heralds the arrival of an Ocado order, there are few interruptions – and little sense of urgency, or haste.

Tom Baldwin, who was Miliband’s media enforcer for much of his time as Labour leader, is here, tapping away at his laptop, putting the finishing touches to a press release about a speech on Europe his old boss will make the next day. But it’s a gentle kind of spinning, this: a one-off return to the fray. The two old friends chat amiably about their families, exchanging titbits of news. A tiny plastic Octonaut figure, abandoned face down on the carpet beneath a chair, is a reminder that this is a family home; for Miliband’s two sons, a place to play.

A year ago, it was a place to plot. Miliband’s advisers – Torsten Bell, Greg Beales, Marc Stears, Baldwin, Stewart Wood – would gather here at weekends to talk tactics, draft speeches and shore up their man. Together with their Tory opponents, most opinion pollsters, and much of the press, they believed they could carry Labour over the line into government.

That belief persisted right up until election night, when the BBC’s 10pm exit poll correctly predicted that the Conservatives were in the lead. In fact, voters had delivered what David Cameron later called “the sweetest victory of all” – an overall parliamentary majority for his party.

Facebook Twitter Pinterest Miliband leaving Labour party HQ in London the day after the 2015 general election. Photograph: Justin Tallis/AFP/Getty Images

“It’s hard,” says Miliband, of that defeat. “It’s very hard; it’s definitely hard. And you know it’s hard because of what you see happening to the country. The people who are suffering; what’s happening to the NHS; just right across the board. And that’s the sense of sadness and regret that one has about the election result.”

There was personal hurt, too, it has taken him a long time to feel ready to return to the public fray. He remains an MP, but has been scrupulously quiet throughout the ructions in his own party that have marked the leadership of Jeremy Corbyn.

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“My view right from the moment I stood down was that I’m not going to get into a running commentary on my successor, and I think that’s the right position. I was always going to be 100% supportive of whoever succeeded me, and that is my position in relation to Jeremy.”

But in the wake of last year’s catastrophic defeat, few of his colleagues – on either wing of the party – were so reticent. Leftwingers, including some around Corbyn, trashed Labour’s manifesto as “austerity-lite” for accepting that some spending cuts might be necessary. Rightwingers quickly junked policies such as the freeze on household energy prices as too “anti-business”.

Still others blame him for failing to stay on as leader and stabilise the party in the wake of the defeat – and for changing the rules for selecting his successor, in a way that some feel allowed johnny-come-lately £3 supporters to swing the party too far left. “He broke the Labour party” is a line I have heard from more than one senior figure, I tell him.

“I don’t buy that,” he says. “The interesting thing is that this notion of what is essentially a primary system, whereby all of the members and supporters of the party get to vote, is actually something that all wings of the party were proposing and supporting.

Facebook Twitter Pinterest ‘I was always going to be 100% supportive of whoever succeeded me, and that is my position in relation to Jeremy’ … Miliband with Corbyn. Photograph: Hannah McKay/PA

“Sometimes I hear that people feel a sense of ambivalence about the fact that we’ve doubled our membership. I don’t feel ambivalent about that at all, because I think the only way you change things as a political party – and in a way this is one of the deeper lessons I learned from what happened – is you need the people on the ground; you need to be making the argument.”

Given his obvious enthusiasm for ideas – “the lifeblood of politics”, as he calls them – a thinktank chair or a place in the wonkier lane of the lecture circuit would have been an obvious next move. And he has been “writing and thinking” he says – as well as having the chance to walk the kids to school.

But he has also thrown himself back into campaigning in his constituency of Doncaster North, trying to discover what this re-imagining of politics from the grassroots up might mean in practice.

Late last year, he went on the six-day community organising course run by Citizens UK, the successful campaigning movement that has fought for a living wage in London and beyond, and tries to give local activists the tools they need to tackle injustice in their communities. “That was incredibly eye-opening,” he says. “Part of what I’ve tried to do in my constituency is apply that to us as a political party.”

So the man who had hoped to take on “predatory” capitalists with the might of the British state at his elbow, has instead been manning a stall on the high street in Mexborough, in his Doncaster constituency, urging local people to avoid loan-to-own retailer BrightHouse, which has been accused of charging up to three times as much as alternative retailers, and use the local credit union instead.

“Scepticism and cynicism about politics is so great that one of the best counters to it is what you can do at a local level,” he says. “This BrightHouse campaign has come out of me engaging with our new members, and saying that being a member of the Labour party is not about asking ‘What can Jeremy do for me?’ or ‘What can the mayor of Doncaster do for me?’; it’s about what can we do ourselves in the community.

“Now I think what’s got to be done – and I know Tom Watson [Labour’s deputy leader] takes this incredibly seriously – is that those 400,000 people have to become part of what I never managed to really do completely, which is to make Labour into a genuine community organisation: to use those people to make them feel it’s not simply about attending meetings or engaging in internal events, it’s about reaching out.”

He has been working on climate change, too – a cause he has believed in since his days as secretary of state for energy and climate change in Gordon Brown’s government. With cross-party backing, he recently managed to persuade the government to agree to back an amendment that enshrined in law the zero-emissions target Britain signed up to at the Paris climate change talks. “I think that’s an important thing I could do by building a cross-party alliance of people”, he says.

Facebook Twitter Pinterest Ed Balls and Ed Miliband, then advisers in Tony Blair’s Labour government, in 2000. Photograph: Martin Argles/The Guardian

And on Europe, his speech aimed to deliver a warning (from a politician no longer caught up in the day-to-day dogfights in Westminster) of the long-term risks of flouncing out of the European club – particularly for any future Labour leader who succeeds where he failed and wins back power. “Just think about all the things you’d want to do; and think about how much more difficult it would be outside the European Union: things I really care about – inequality, how you create decent jobs; tackling tax avoidance; guaranteeing workers’ rights. All of these things become much more difficult when you’re on your own.”

Miliband was asked to speak out because senior figures in the Remain camp fear that Labour voters will regard the referendum as a family row among Conservatives, instead of a vote about Britain’s future, and stay at home. “You can’t allow the moment to obscure the long-term impact of this decision for progressive politics,” he insists.

He adds that leftwing critics of the EU are deluding themselves if they think losing the shackles of Brussels would allow Britain to implement a radically different set of policies. “There just isn’t a version of ‘socialism in one country’ around in the 21st century,” he says. “I think it’s really important that we don’t fall for this nirvana of ‘Let’s just get out and we can create a socialist Britain’.”

Corbyn himself has sometimes flirted with this approach in the past, and some Labour backbenchers accuse their leader of being lukewarm on Europe, but Miliband insists: “Jeremy is as passionate about this as I am. The thing I say to Labour activists is [that] we’ve got a responsibility that goes beyond the here and now – to allow future Labour governments to be able to achieve the kind of progressive change that we want to see, and we’ve also got a responsibility as Labour voters.”

He adds “nothing can be taken for granted in this. Sitting on our hands is not the answer in this referendum. Sitting back, watching the Tories tear themselves apart.” Afterwards, Baldwin asks whether “neither sitting on our hands, nor rubbing our hands”, is a nicer turn of phrase. Miliband shakes his head: “Doesn’t sound very me.”

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He goes out of his way to praise Corbyn, whose outriders in the parliamentary party feel so besieged they have been drawing up lists of those they consider to be hostile – a fact that emerged this week, unleashing fury on the right of the party, and derision from the prime minister.

We spoke before the list emerged, but Miliband said nothing to justify his inclusion as “core group negative”, indeed offering a far more positive review of the leader’s performance than many of those deemed “neutral”.

“I thought Jeremy did incredibly well at the budget response in the chamber last Wednesday, and I know from experience how difficult that is,” he says.

As it turned out, Miliband’s carefully choreographed return to frontline political life provoked the merest flicker of interest – drowned out by the political maelstrom that engulfed the Conservative party after the resignation of Iain Duncan Smith, and the fatal terrorist attacks in Brussels.

At times, while listening to Miliband, it feels as though the way he has rationalised the bruising events of the past 12 months or so is by intellectualising them – by ascending to the lofty heights of the historian, leaving behind the clumsily gulped bacon sandwiches, the 8ft 6in “Ed Stone”, and even the act of political fratricide that saw him seize the Labour crown.

Facebook Twitter Pinterest Ed Miliband and his brother, David, after Ed was elected Labour leader at the party’s annual conference in 2010. Photograph: Martin Argles/The Guardian

“I think part of the thing that is important to me, and is important to Labour supporters, is that the fight goes on,” he says. “The fight goes on in relation to this budget, in relation to Europe, and in a way, the history of progressive politics is that there are setbacks – significant setbacks – and you have to overcome that. But obviously it’s tough.”

Ironically, some of the ideas Miliband championed continue to strike a chord – George Osborne pinched his promise of a generous rise in the minimum wage (punchily rebranded as the “national living wage”); and shadow chancellor John McDonnell’s pledge to “change the rules of capitalism” is pure Miliband.

In the US, Bernie Sanders’ rhetoric about the raw deal ordinary workers get from big business, and his appeals for a responsible capitalism, chimes with Labour’s approach.

And Osborne’s standing with the public has plunged since the abstract manifesto pledge of “welfare cuts” was translated into specific proposals to slash tax credits for working families, and to cut the amount disabled people receive to help them dress themselves or go to the toilet.

Miliband describes this as “the mask slipping on what the Tories are and what they stood for. You can’t talk one nation and act two nations, and that’s what they’re doing.” But even here, he sounds at least one step removed from the fray.

When our chat is over, and the Guardian’s photographer asks Miliband to move to a scuffed, pale green button-back chair, he glances for approval at the man whose job it once was to ring up journalists and castigate them for failing to give his man a fair crack. The chair passes muster, but you sense it’s not so much because it projects the right image – but because it doesn’t matter any more.

• This article was amended on 25 March to clarify that the BBC’s general election exit poll predicted that the Conservatives were in the lead, not that they would have a majority.