Eleven days after his election as Labour leader, Jeremy Corbyn’s office is festooned with cards congratulating him on his landslide victory. Corbyn proudly shows me one from the children of Duncombe Primary School in Islington, north London. “Please remember, just as you have always been there for us, we are there for you,” it reads. “They’ve put a tie on me, the devils,” Corbyn quips of the drawing of him on the front.

Corbyn’s first week as leader was more shambolic than either his supporters or his opponents had anticipated. His shadow cabinet reshuffle led to accusations of a “woman problem”, when only men were chosen to represent the great offices of state (though the final team was, for the first time, majority female). He was then denounced by Labour frontbenchers for not singing the national anthem at the Battle of Britain memorial service at St Paul’s Cathedral and forced to pledge to campaign for EU membership during the referendum after protests by the shadow foreign secretary, Hilary Benn, and others.

Having assembled a full frontbench team and with the party gaining 62,000 new members since his election, however, Corbyn is in high spirits as he prepares for his first conference in charge. He and his staff have taken up residence in parliament in the Norman Shaw South building, home to the leader of the opposition since the time of Michael Howard. His new press spokesman, Kevin Slocombe, formerly of the Communication Workers Union, sits in on our interview. Other aides, including his chief of staff, Simon Fletcher, who held the same role for eight years during Ken Livingstone’s London mayoralty, and his director of policy and rebuttal, Neale Coleman, who worked for Livingstone and for Boris Johnson, continue with conference business.

By common consent, leader of the opposition is the toughest job in British politics, especially so for a Labour leader. “It’s fascinating: a lot of pressure, a lot of different things to do all the time. And I’m enjoying it,” Corbyn tells me when I ask him how he is handling the role. “There’s a very large number of people all over the country who have a great deal of advice to give me . . . A lot of the stuff is very interesting, actually, and I do read a lot of it. The crowdsourcing we did for Prime Minister’s Question Time was absolutely fascinating.” Corbyn says that he intends to continue to put inquiries from members of the public to David Cameron on Wednesday afternoons. “I want to be seen – and I am – to be asking questions that people are asking. There will always be an element of that in it. But I’ll probably choose fewer subjects in future, because if you choose three subjects, you can’t follow through properly. Maybe choose one area and follow it through in six questions.”

When I ask about his relations with the media, Corbyn laments that they have not paid “the slightest” attention to his demand in his victory speech for them to leave his family alone. He says: “I don’t expect any fair treatment from some of our media to me personally. That goes with the job. I have already said and will continue to say that I won’t respond to personal abuse and I never make any personal abuse, ever, to anybody. I just don’t do that kind of politics.

“What I find appalling is the intrusive nature towards my extended family. I have asked them [the media] to respect the privacy of people. They don’t. I just find it depressing. But I have to say a big thank you to all of my extended family, some of whom I’d never met before, some of whose existence I was barely aware of before. Thank you for your kindness and solidarity and I’m sorry for what you’ve been put through.”

MPs from all wings of the party tell me privately that they expect Corbyn either to resign or to be ousted before 2020. But when I ask him whether he is committed to remaining leader until the general election, he replies: “Yes.” Most predict that, were he to do so, the electoral consequences would be disastrous for Labour. A former shadow cabinet minister told me that the party would fall below 200 seats for the first time since 1935. Yet Corbyn declares unhesitatingly that Labour can win.

“What I’ve observed is something very different among the key groups who didn’t vote in the election, particularly young people and working-class Labour supporters who felt alienated by what we were saying and what politics was offering them,” he tells me. “Also, interestingly, in discussion – it’s not terribly scientific, but talking to people in various places who voted Ukip or Tory or Green – they are open to a debate that is about a different way of doing politics, which is about class politics, rather than consumer politics.”

MPs have recently been recalling the plot of Chris Mullin’s novel A Very British Coup, in which the military and political establishment seeks to overthrow the left-wing Labour prime minister Harry Perkins. In a case of life imitating art, a senior serving general told the Sunday Times that Corbyn would face a “mutiny” from the armed forces if he imposed severe defence cuts, scrapped Trident or withdrew from Nato. “The general staff would not allow a prime minister to jeopardise the security of this country and I think people would use whatever means possible, fair or foul, to prevent that,” the general told the paper. When I raise this with Corbyn, he says: “I don’t know who this general was and apparently he’s been told off by his superiors already and I hope so. We live in a democracy and I think it’s surprising that somebody would make those kinds of statements. But, as I say, I don’t know who this person was, I don’t know the context in which the comments were made and I find it surprising that they haven’t been named.”

But to the political story of the week ­– the allegation that David Cameron put “a private part of his anatomy” into a dead pig’s mouth – Corbyn has “absolutely no response at all”. He adds, however, “I am concerned about the alleged knowledge, or not, of the non-dom status of some of his friends in the House of Lords.”

The Tories have signalled their intention to seek Commons approval for UK military action against the so-called Islamic State in Syria when the conference season ends, an issue on which the shadow cabinet is sharply divided. Will Corbyn offer frontbenchers a free vote? “We haven’t reached that stage yet, because we don’t actually know what, if anything, the government is going to bring before parliament . . . Clearly, there may be differences of view and Ed Miliband went through the same experience and ended up with a fairly united position. I will obviously attempt the best unity I can get on this . . . My views on military interventions are very well known and they haven’t changed.”

Corbyn has long spoken of his desire to re-establish Labour’s annual conference as the party’s pre-eminent decision-making body. For the first time in decades, delegates will be given the chance to vote on a motion on abolishing Trident, a stance endorsed by Corbyn but opposed by many in his shadow cabinet. Would unilateral nuclear disarmament become party policy if the motion were approved? “Well, it would be, of course, because it would have been passed at conference.”

He adds, however, “I understand the principles of dissent in parliament. I’ve expressed a bit of dissent myself in my time [he has voted against the party whip 534 times since 1997]. I respect that and I hope others will respect it, as well.” Corbyn has spoken out against mandatory reselection, the mechanism that some on the left of Labour hope to deploy to unseat right-leaning MPs, but he concedes that it would “absolutely” become “party rules” if activists voted in favour of the process at conference.

When Corbyn used his speech at the TUC conference on 15 September to declare his support for the abolition of the household benefit cap (which will be reduced from £26,000 to £23,000 in London and £20,000 elsewhere), he was immediately contradicted by the shadow work and pensions secretary, Owen Smith, and the shadow equalities minister Kate Green who insisted that party policy remain to support a limit. The response from Corbyn, who says at the start of our conversation that he has “a bigger mandate than anyone else has ever had” (he won 251,417 votes, 59.5 per cent of the total), is striking. Having previously vowed to seek “consensus”, he asserts his authority over his shadow cabinet. “It’s what I’ve put forward as leader and I’ve made that very clear . . . We will now oppose completely the Welfare Reform [and Work] Bill.” He says: “In my own constituency, the benefit cap has had the effect of social cleansing, of people receiving benefit but the benefit is capped; therefore, they can’t meet the rent levels charged and are forced to move. It’s devastating for children, devastating for the family and very bad for the community as a whole.” He emphasises, however, that he does not oppose the overall government welfare cap of £119.5bn.

As well as vowing to oppose the current Trade Union Bill, Corbyn says that he supports the repeal of the anti-union laws introduced in the 1980s (“Yes, I do”) , which prohibited flying pickets and solidarity strike action.

“We’re going to be discussing and consulting on a positive rights-at-work agenda that is at least in line with the International Labour Organisation conventions . . . A Labour government would have an equivalent of a ministry of employment, employment rights. That’s the area we’re looking at. I don’t know what we’d call it. It shouldn’t just be part of [the Department for Business, Innovation and Skills].”

Perhaps the most divisive decision Corbyn has taken since becoming leader is the appointment of his campaign manager and left-wing ally, John McDonnell, as shadow chancellor. A more abrasive character than his leader (“Jeremy is teaching me to be a nicer person,” he said), he has had to apologise for joking about assassinating Margaret Thatcher and for his past praise of the IRA. When I ask Corbyn whether he anticipated the level of criticism, he pauses and sighs. “I always knew there was going to be some criticism made of it. He is a very close friend of mine, as everybody knows. He is a brilliant guy on economics and the ideas that go with it. I think it’s very important that the leader and shadow chancellor are thinking in the same direction and we’re certainly doing that. John has made a great start, setting out what his economic policies are.”

Less than a fortnight after his election, some on the left believe that Corbyn has already conceded too much. He has vowed not to oppose EU membership and not to support Nato withdrawal, and McDonnell has retreated from his most radical economic stances (Tariq Ali described his Question Time performance as “craven”).

When I ask Corbyn whether he wants to reassure his supporters, he says: “Listen, I’m very proud to have been elected to this post. I’ve set out my views very well, I hope, on what I thought was a different way of doing politics, which was more inclusive . . . There’s going to be policy changes and I did say, all the way through the election campaign, that electing me was only part of it. My job was to open up policymaking and that’s what I’m doing.” The message is clear: Corbyn has a mandate – and he intends to use it.

Q&A: A united Ireland, potatoes and chatting to Jens Lehmann

George Eaton Favourite book?

Jeremy Corbyn Madame Bovary.

GE Favourite band?

JC The Animals.

GE Favourite Labour leader?

JC There’s a number, some of whom I’ve never met, some of whom I have. Eve of conference, I’m going to the book launch on the centenary of Keir Hardie. I’ve written a chapter for the book on his legacy for the peace movement around the world.

GE You mentioned that you spoke with Ed Miliband. Have you spoken to any other former leaders?

JC No, there’s not very many of them around! I’ve spoken to Neil Kinnock many times, because he lives in my constituency and I bump into Neil quite often locally. I’ve spoken to

Ed Miliband quite extensively.

GE What advice did [Ed] Miliband give you when you spoke?

JC Balance your life, which I’ve tried to do. Well, I hope so!

GE How’s your allotment?

JC My allotment’s great, my allotment’s splendid. I was there at the weekend and I have a large supply of potatoes fresh from my allotment and vegetables and many other things, so my allotment is fine. My allotment holders are very happy. All of my fellow allotment holders are very happy people. We get along just fine.

GE Favourite Arsenal player?

JC Of all time, Ian Wright. Plus, Dennis Bergkamp. And the one I really enjoyed talking to was Jens Lehmann. I like him very much.

GE Favourite demonstration?

JC Got to be the 2003 Stop the War demonstration.

GE Do you support a united Ireland?

JC It’s an aspiration that I have always gone along with.

GE Favourite country to visit?

JC That’s impossible, I’ve been to so many. I’ve been to, in my life, 70 countries around the world. They’re all interesting, they’re all fascinating, they’re all different. You can learn so much history from everywhere you go to. I’ve visited, I suppose, Latin American countries more than anywhere else in the world, partly because my wife’s from Mexico and so we obviously go to Mexico and Central American countries. Everywhere you go is interesting. My brother lived in Papua New Guinea, amazing place.

GE What’s the first thing you’d do as prime minister?

JC Deal with the housing crisis, deal with the inequality crisis, deal with the poverty crisis in Britain. And configure a foreign policy that is about peace, that is about human rights, that’s not about military intervention around the world.

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Now listen to George discussing Jeremy Corbyn and Labour on the NS podcast: