As we settle down on the sofa, Hilary Benn launches straight into a story about a recent visit to South Africa, where the Department for International Development is supporting a Church of England-run project in Pretoria for people with HIV/Aids. "We followed a man called Victor around and he was pulling a plastic container full of food up and down the paths in between corrugated iron walls. We knocked on one door and an old lady opened it. She is living in a room, ten foot by ten, with a dirty curtain separating her living space from where she sleeps, and she was blind." Benn explains that Victor gave the blind lady an apple, two rolls and margarine, and that he calls on her most days of the week. The lady told the British dignitary that a man had offered to concrete over her earth floor for 50 rand but had run off with the money.
The bishop and local councillor accompanying Benn prom ised she would get her concrete floor. He draws this conclusion: "Things like that remind all of us why we do this and why a lot of the things that allegedly pass for politics cannot be compared to trying to help people change their lives." It is a classic politician's story, designed to show compassion mixed with a desire to make a practical difference.
Such a response, Benn says, is another expression of the phenomenon eating at the heart of politics: cynicism. His deputy leadership campaign, he claims, is an attempt to re-inject idealism into the Labour Party and a government whose confidence has been undermined by Iraq and cash for honours. "The thing that worries me more than anything else is losing faith in the capacity of politics to change things. I don't mean scepticism, criticism, querying, but I do mean cynicism." We suggest that Labour, with its culture of spin, is at least partly responsible. "The truth is, we are partly to blame, you [the media] are partly to blame, and the culture of excessive expectation followed by inevitable disappointment is to blame," he says. "People are yearning for a politics that tells it straight: that being in government is difficult, that there are tough decisions that we have to make sometimes."
Benn likes to use the phrase "politics is not shopping", and here his political philosophy, as well his voice, resemble his father's. "Politics is not about 'I'll have a bit of this and a bit of that and in about five years' time I might shop with someone else'. Politics is a process, and there has to be a continual conversation between those who govern and those who give their consent to be governed." The Labour leadership should listen more to the members, and the members should listen more to the public. But the only specific proposal he suggests is that the position of party chair should be elected.
Asked what unique qualities he will bring to the job of deputy, he is equally vague. "We need someone who is going to offer honest advice and ensure the voice of the party is heard inside the highest reaches of government. We need someone who's going to listen and is good at working with people. And whoever gets the job, the party has got to demonstrate we are passionate about social justice."
In fact, Benn is vague on just about every policy issue we raise. We ask him about his year as prisons minister. Does he take any responsibility for the overcrowding crisis? He ducks the question, saying that there is a fundamental problem with the public's view of the effectiveness of community punishments. Even in his area of greatest expertise - education - he has no hard policy ideas, or else he is keeping them even closer to his chest than the Chancellor does. He is a champion of comprehensive education, inspired by his mother, the campaigning left-wing educationalist Caroline Benn. Educated at Holland Park Comprehensive in west London, he became education chair at Ealing Council and later worked as special adviser to David Blunkett. It might seem reasonable to expect big new ideas, but he insists on speaking in abstractions. "Like a lot of things in life, in the end it's about getting the balance right - the balance between high expectation, the right support and resources - and making sure that you tap the potential enthusiasm of the next generation."
Benn has been tipped for the job of foreign secretary in a Gordon Brown cabinet and the Chancellor is known to be an admirer of his work at DfID. So, it seems only right to push him on Iraq and Iran, and the theory and practice of military intervention that have so divided the left.
Benn stands by his decision to back the war in Iraq, though he says he has never thought about anything harder in his life. "In the end I voted in the way I did because I thought it was the right thing to do. I respect those who take a different view. I think if you look back over the history of Iraq - all the resolutions breached, all the slaughter that Saddam was responsible for - one of the questions we have to ask ourselves as a world is: Why weren't we more effective at dealing with it earlier?" Iraq, he says, poses a broader question. "We haven't yet found, as a world, an effective means of protecting human beings who face that kind of treatment." He lists Darfur as the latest of many dilemmas, but points to the joint mission of the UN and African Union as a positive step. Benn talks repeatedly of the need to bolster multilateral institutions, but, like so many who supported the Iraq war, finds it hard to reconcile that view with the events of 2003 in which George Bush and Tony Blair ignored the actions of the very UN inspectors who represented multilateral engagement. He then addresses a point at the heart of the anti-war case - the inconsistency of the way the world applies international norms. "We are hypocritical and inconsistent about when we choose to act, but the fundamental uncomfortable question isn't going to go away, is it?"
So we attack Iraq, but what about that other member of the axis of evil, Iran? With the Americans going down a familiar route of producing "evidence" of malfeasance, and with the British government uncomfortably saying little to deter them, we ask Benn what chances of a US or Israeli military strike on Iran's nuclear installations. "You'd have to ask them. I don't think that would be the right thing to do at all. That's my view. I can speak for myself, I can't speak for others."
His answer is curt, but revealing. His awkwardness grows as we press the point. So why would military strikes not be the right thing to do in this case, if it was right against Saddam? "One, because we've got a process in relation to sanctions. Two, because there's clearly a political debate going on in Iran and I'm a very strong believer in trying to resolve those issues by dialogue and debate." But what if the development of an Iranian nuclear bomb continues? Why not intervene? "Because I'm not in favour of military action against Iran."
We give him every opportunity to leave the door open for military action and ask again: Why not intervene? "Because I'm not in favour of it." But what is the difference between Iran in 2007 and Iraq in 2003? "I think we can resolve this in a different way, because of the politics in Iran. I think that's a very, very big difference."
Gordon Brown has let it be known that he wants to develop an independent British foreign policy. He could learn a lot from Benn's work at DfID, which has often been at odds with the Bush administration. On Aids and drugs, the US approach could not be more different from the British. The Americans, influenced by the Christian right, have pursued a policy of drug eradication coupled with sexual abstinence, even influencing the UN to limit funding for needle exchanges and programmes that combine sex education with distribution of condoms. Instead, he has followed a non-moralising, "harm reduction" approach. "You've got to talk about sex, however embarrassing it is. Human beings have sex and they shouldn't die because they have sex - you should make condoms available. And you have to get treatment to people and fight stigma and discrimination because that encourages people then to be open about how to fight the disease."
He is dismissive of the American way. "Abstinence-only programmes are fine if you want to abstain, but not everybody does. Men have sex with other men and we have to work with them. Some people pay for sex: you've got to work with prostitutes. Some people, heaven knows why, inject themselves with drugs: clean needle-exchange programmes reduce the likelihood that the HIV virus is going to be passed on. It's very clear and we've just got to be straight about it."
We ask Benn for his assessment of the Bush administration. "Pretty Republican," is all he will say. Does he agree with Peter Hain's view that it is the most right-wing in living memory? "I'm not going to comment on that." Why not? "Because I don't want to. What I would say is where we agree, we work together, and where we don't agree then we say what we think." On climate change, he says the UK has opposed US scepticism about the existence of global warming. He threatens to wrestle us to the ground (metaphorically speaking) if we can come up with "a world leader who has done more to argue the case for a global agreement to tackle climate change than the Prime Minister". "It is a caricature that America just has to say, 'Britain, we want to do the following' and we say, 'Yes sir, no sir, three bags full sir.' It's just not true."
Hilary Benn came to parliament late, but his rise has been swift. He has made no enemies, and caused no offence. He has yet, however, to be fully tested. International Development is a good-news department. Now he is the bookies' joint fav ourite, with Alan Johnson, to succeed John Prescott as deputy prime minister. The public seems to buy his pitch that he is "a pretty straight guy". There's little reason to suggest that he would not do a good job, but if he could be persuaded to take the bold policies he developed at DfID into a wider international arena, Gordon Brown might start hoping that Benn will lose, so that he can make him foreign secretary.
Hilary Benn: The CV
Research by Sophie Pearce
Born 26 November 1953. Son of Tony and Caroline Benn
1979 Elected to Ealing Council
1983 and 1987 Unsuccessfully contests the Ealing North constituency
1986 Becomes youngest chair of Ealing's education committee
1997 Appointed special adviser to David Blunkett , Education Secretary
June 1999 Elected MP for Leeds Central. The turnout of 19.5 per cent is a postwar low
June 2001 Appointed under-secretary at the Department for International Development
May 2002 Appointed under-secretary at the Home Office
May 2003 Appointed minister of state for international development
October 2003 Promoted to Secretary of State for International Development
January 2004 George Monbiot accuses Benn's department of doing "more harm than good", for allegedly giving more "aid" to the Adam Smith Institute than to Liberia or Somalia
May 2005 Re-elected MP for Leeds Central
March 2006 Disowns parliamentary aide Ashok Kumar after Kumar calls for Tony Blair to stand down
September 2006 Withholds £50m payment to World Bank in protest at conditions attached to aid for poorer countries
October 2006 Announces candidacy for deputy leadership 25 years after his father, Tony, fought and lost the same contest