"A sure sign I'm succeeding," he laughs again. "When you announce your strategy in advance that you are going to go for somebody because you're really relishing it, it's a sure sign that actually the opposite is true." For him, it just goes to confirm that the government is both "failing" and "flailing".
Ed Miliband returns to Manchester, the venue of his narrow victory in the leadership contest two years ago, in a more solid position than many critics or friends then expected. His party looks more united than the fractious coalition and the lack of overt sniping from within about his leadership is the envy of both David Cameron and Nick Clegg.
The Labour leader says he is "pretty satisfied", while acknowledging "we've got a lot more progress to make". Some of that work has to be on himself. Labour's continuing lead in the opinion polls means that people will start to appraise him as a potential prime minister. Many are as yet unconvinced that he possesses some of the key qualities of leadership, as our poll underlines. That makes his conference speech an important opportunity to showcase his character and his beliefs.
"I want the speech this year to be about me: who I am, why I am in politics. Secondly, how are we going, in concrete terms, to tackle the economic challenges the country faces? People need to know that. And, thirdly, what kind of Britain does Ed Miliband as prime minister want to create?"
He plans to explain why he chose a political career rather than follow his father's footsteps into academia. "If you see an injustice, you don't just shrug your shoulders, you don't just write an academic book, you do something about it. That's my upbringing. You might say, well, my Dad was an academic, but he was not someone who had contempt for people who went into practical politics.
"I remember having this conversation with my dad – he died in '94 so it must have been the year before that. I said 'Look, you know I'm drawn to politics. I'm not really drawn to academia.' And he said: 'Well, do it. You've got to follow what you believe.' "
Mind you, Ralph Miliband, a committed Marxist, wrote that the parliamentary road to socialism which has been pursued by both his sons was doomed to failure. Reminded of this, the Labour leader laughs.
"It's funny, actually. I do remember meeting his friends after he died and they said: 'Ralph was such a great man. He'd be so sorry what's happened to you.' A sort of: where did it all go wrong? Where did you go off the rails? Sort of the equivalent of taking drugs."
Miliband's enthusiasm for the importance of ideas in politics is refreshing, but it comes with its problems. One is a personal struggle to translate theoretical concepts such as "predistribution" into practical policies and language accessible to voters who don't live in academic seminar rooms. Another is that he only has to mention the author of a book he might have read for that person to be described as the Labour leader's latest "guru".
He grins in recognition of the point. "Disaster having any gurus, I think." It's often not that healthy for the gurus themselves. Maurice Glasman, whom he made a peer, has gone rather quiet after making disobliging remarks about Miliband's leadership style.
"Yeah," he agrees. "It's a disaster for the gurus. The gurus then sneeze and it's interpreted as a sort of bitter attack on me."
Glasman did more than sneeze. "Well, OK, it was a sort of flu."
The latest alleged guru is Tim Soutphommasane, who is so close to the Labour leader that Miliband cannot remember his name. "There's now this new Australian bloke who's my guru."
Have they actually met? "I met him for 15 minutes or half an hour."
This year's speech will build on the theme of "responsible capitalism" that he made the centrepiece of his address last year. That got a rough reception from many quarters, which was made worse when he and members of the shadow cabinet floundered explaining exactly how a Labour government would distinguish between "the predators and the producers". But after another year of financial scandals, even some of the critics now accept that he is on to something potentially powerful, allowing him to say "I was on the right lines".
"We live and learn," he says of the confusion that followed last year's speech. "But there's two more deeper things I'd say. One, ideas matter in politics. Ideas matter a lot more than people realise. When Cameron comes along and says 'hug a husky, hug a hoodie' and now he wants to lock up the hoodies and who cares about the huskies, I think it massively undermines not just his authenticity. When events, dear boy, events push you around you've got to have a project which you stick to.
"Our political world is quite contemptuous of ideas often, but actually ideas matter a lot more to political success than people realise.
"I've got a very clear direction. That's what's sustained me. You have ups and downs and I suppose the thing I've always known is I've had a very clear sense of how the country needs to change. Responsible capitalism? It's not what they say on the streets, but it's a very clear agenda about how you change our economy so it works for all working people and not just a few people at the top."
It may be clear to him, but he now seems to have a better appreciation that it is also imperative to express it coherently and attractively to those people on the street. He takes the point that no one is going to march to the chant: "What do we want? Responsible capitalism and predistribution! When do we want it? Now!"
Agreed, he says. "It's got to translate into real things", which is a cue for a major announcement in respect of the banks. He creates some context by relating an anecdote about Alan Henderson, a businessman in Putney, south-west London, whom he met in July. Henderson had run a successful sign-making firm for four decades.
"He had been with the same bank for 40 years. Four years ago, he took out a loan, but he also took out what's called a dual interest rate swap. After a long discussion with him, I couldn't understand what it really was or how it worked, but suffice to say he lost hundreds of thousands of pounds. His family has been going through a nightmare. He's had to make 10 people redundant. What does that say to you? You've got to change the culture so that high-street banks aren't the arm of a casino operation."
The Miliband solution is full implementation of the recommendations made by the Vickers commission, not the "watered down" and delayed version of the reforms proposed by the coalition.
He gives an ultimatum to the banks. "I'm saying very, very clearly – there's two things that can happen. The banks can change direction and say we're going to implement the spirit and principle of Vickers to the full, which means the hard ringfence between retail and investment banking. Either they do that or I'm giving a very, very clear message which is that the next Labour government will just by law break up retail investment banks. You'd do what they call Glass Steagall."
That is the former American law that imposed a rigid division between retail and investment banking so that the speculative excesses of the latter could not endanger the former. "It is a drastic step doing Glass Steagall. I want to get the culture change whatever way I can get it. If it can be done in another way, I'll do it." But if the banks don't heed his ultimatum, it will be one of the very first acts of a Labour government.
This initiative will be attacked by critics on at least two grounds. One: it will put fragile financial institutions in jeopardy by cramping their profits. Two: it will provoke banks to abandon Britain and move their operations abroad, taking jobs and tax revenues with them. "On the first, the best way of guaranteeing safety is by having a proper culture change," he responds. "On the second, we can't give in to those arguments any more. For too long governments have succumbed to those kind of arguments and we haven't done the right thing for the country."
How is this meaningful to the voter in the street? "For the ordinary person" it would mean a lot more confidence that high-street banks were "going to sell you simple, comprehensible products [and] the focus of the bank was serving you not on how they're doing playing the international money markets."
It is interesting that he, not the shadow chancellor, is launching this initiative. The state of his relationship with Ed Balls is a persistent source of speculation. Is it true that he once rebuked the other man for using his BlackBerry at a shadow cabinet meeting?
"Absolutely 100% untrue," insists Miliband. "I remember at my first shadow cabinet meeting as leader – I will let you into the magic – I said 'Let's try and be sparing in the use of BlackBerrys. Absolutely was not directed at Ed Balls. It's total, total rubbish."
Even if that particular story is untrue, there are well-sourced accounts that their relationship can be difficult.
"Look, we go back 20 years." That could be a lot of the problem. "We work incredibly closely together and we have an incredibly good relationship." Balls wasn't his first choice as shadow chancellor (his pick was former home secretary Alan Johnson). So will Balls definitely be chancellor if there is a Labour government? "I think I'll make my cabinet when it comes to ... I think measuring the curtains is not my style."
So Balls is not guaranteed to be chancellor? "Oh come off it. No." Why not? "You start with one member of the cabinet and then you move on to all of them. Look. Ed and I work incredibly closely together and we're a team and we're going to be a team going into the election."
A complaint sometimes heard about Balls is that he smothers initiatives by other members of the shadow cabinet. "It's always the case, if you're the shadow chancellor, that you've got be watchful about tax and spending, and making sure that people don't make commitments. I don't remember Gordon [Brown] being very popular before the 1997 election with colleagues. No shadow chancellor is popular with colleagues because you've got to be tough."
Because of his reputation and pugilistic build, voters probably don't have much trouble imagining Balls being tough. For Miliband, not being capable of taking tough decisions is one of the serious weaknesses in his personal image identified by our poll.
"The way I think about it is that people form a view about your character and who you are over time. You know, no one wants to repeat Clegg mania, do they? Clegg mania which then became Clegg phobia."
When voters look at him, does he think they see a future prime minister? "Well, that's for them to decide."
They may decide – as they did last time – that they are not entirely convinced by any of the candidates for prime minister and produce a hung parliament. He has said before that he could never work with Clegg in a coalition. Is that still the case?
"I'm not interested really in that sort of poker game, but, you know, the position hasn't changed. The card I'm playing for is a majority."
guardian.co.uk © Guardian News and Media Limited 2010
image: © EdMiliband