It may be a question that has never crossed your mind, not even very late and very drunk, but what is the opposite of John Prescott? Take away the belly, the chippiness, the mangled words, blokey forthrightness and what do you get? Step forward anti-Prezza, the bookies’ favourite to succeed him as deputy leader . . . the slim, eloquent, rather rarefied Hilary Benn.

Mr Benn is good at not being things. He is not a meat-eater, he is not a drinker, he is not on the left, nor the right, and he is, of course, not his dad, Tony. As Hilary says in response to questions about his famous father, “I’m a Benn, not a Bennite”, and he tells us for good measure that he is not a Blairite or a Brownite either.

So what, or who, is he? We meet in the House of Commons cafeteria, where, as a security guard sidles up to him for a chat, it is obvious that he is revered as part of a political dynasty (as well as a lot of hard work as Secretary of State for International Development).

But step outside on to the street, we tell him, and no one would know a thing about him. They might guess who he is – Tony Benn’s son – but not what he is. Even compared with the other five deputy leadership candidates, his lack of definition is almost what defines him. And this, in the end, is curiously what is most interesting.

“Do I fret about these things? I don’t, honestly.”

So we sat down for our cup of tea (Fairtrade), hoping to find out about the whole man, the child who was taken to see Churchill and Attlee as other boys are taken to the zoo, the death of his first wife, which he once, before becoming an MP and never since, spoke very movingly about, as well as getting a sense of his political vision. But we got stuck on the political vision. His first pass at this attacked the “fashionable” mood to refuse to have anything to do with the “pointlessness” of politics.

“Politics is not like shopping,” he said. “If you think that you can sit back and say ‘well, you lot sort it out’, we’re not going to do anything, we are sunk as a society. I believe passionately that politics does change things . . . this is the single most important means that we have for dealing with the problems of the world and helping people to realise their hopes for the future.

“Whether you call that a big idea or not, I don’t really mind.”

That could pretty much, we said, be the slogan of a politician of any stripe; it’s not quite a call to arms to win Labour a historic fourth term. Mr Benn looked surprised: no, he said, he is also “passionate about policy”.

What about education? When Mr Benn was ten – his father had just won a famous court battle to denounce his peerage – he was plucked from his London private school and landed in a local comprehensive.

It was, he admitted, “big and bewildering” but, ultimately, “wonderful”.

“It taught you about getting on with all sorts of people and people came from a very wide range of backgrounds and experiences. And I really enjoyed it, actually.”

So what would his education manifesto be? He is a “lifelong opponent of selection at 11”, saying that Britain is “still dealing with the legacy” of secondary moderns in its adult illiteracy issues. But what about ways in which private schools can contribute more to the state, as his rival Alan Johnson has mooted?

“Ways in which schools can share experience and ideas is a good idea, but what we really need to focus on is the resourcing of our state schools – and I am a supporter of raising the level of expenditure so that all children get the same level of support and investment.”

Mr Benn is keen on listening, he keeps telling us, but you have to listen very hard to hear the fervour for change. He wants to “listen” more to teachers and, with possibly a mild dig at Blair’s tinkering around with academies and trust schools, he added: “In life there’s a balance to be struck between changing the system for a purpose and allowing people to get on with their job.” (Later he stressed to us: “I’m a great believer in balance.” You don’t say!)

Although he is not allowed, by the rules of the deputy leadership contest, to go beyond party policy – of which he tells us he is very supportive anyway – we go on to ask, in a dozen different ways, how he will inspire people. His answers can be so uncontroversial as to be banal.

Then, just as we are giving up and packing up, comes this: “If we can inspire people to campaign against poverty in the developing world then why can’t we inspire people to work with us to overcome poverty here in the United Kingdom?

“We should be passionate about doing something about poverty wherever we find it because in the end that’s what’s going to help change the lives of my constituents and that’s why I’m sitting here, doing this job.”

It is a flash of political excitement, something to get a campaign rolling. And – with apologies for making the obvious comparison – it is a flash of his father’s stirring intensity. The contrast between them is as much outspoken vs retiring as old vs new Labour.

“I have different views from him on a number of subjects, yes. And we’ve always argued, debated politics and the state of the world ever since I was about that high.”

His father narrowly missed becoming deputy leader in 1981; did he want his son to follow in this path too? “Yes, he encouraged me to put myself forward, yes.”

But isn’t it annoying to have an identity framed in relation to Benn senior? “No, I’m very proud of him.”

While his father is considered a national treasure for his strong personality, a genetic stubborn streak shows up in his son. His is not the shamelessness of the politician who decries personality politics one day and then milks his family for publicity the next. It is a genuine quirk.

“It is the case that when I was appointed to the Cabinet, a number of newspapers said can we do a profile and I said no, thank you. Why? Because I think you should get on with the job and let that speak for itself.”

Rightly or wrongly, people do want to know more of who a politician is these days. They want to feel a connection. “They should come and meet me,” he said, “come and talk to me.”

But not everyone can do that, surely. Can he win over the country one voter at a time? “You can come and listen to me at the House of Commons, you can come to meetings, you can ask me questions.”

He once said that the death of his wife and childhood sweetheart at 26 gave him perspective, made him want to make the best use of his time here. This obviously does not include transforming himself into a media celebrity. Does he envy his father’s profile?

“We’re all ourselves, we’re all different. One of the most important lessons to learn in life is, in the end, that you’ve got to be who you are.”

Does it concern him that few people know of him? “Why should I worry about this?”

Because maybe a politician can achieve more, the more popular they become? “I’m very confident in my own identity .... I’m happiest talking about the things we’ve got to deal with. That’s what I enjoy most of all in this job. That’s how you make a difference rather than fretting about image and definition and all of that stuff.”

He can also be drily funny. He told us that he was very proud once to be categorised, in an article about Blairite and Brownite ministers, published by The Times, as one of the few “independents”. But, we say, maybe he was really “unclassified” rather than “independent”, because the journalist couldn’t work out where he stood.

“I’m sorry to have caused you so much trouble,” he said, with a faint, mischievous smile.

Mr Benn is no pushover (but nor can you imagine him ever throwing a punch at someone). He is quietly combative and took all the prodding, goading, references to his dad, and insulting suggestions about being a nonentity, with resilient good humour.

“I love a good argument,” he said, in parting, and roared with that fiercely loud, unmistakeable Benn laughter. Mr Benn is neither a traditional political barnstormer, nor someone whose modest charm broadcasts well in the modern media age.

But he could well win over voters, one by one.

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