Later tonight, he'll be taking a group of politics students up to London for the live studio segment of This Week, at which he's to be the expert guest. He's probably also got some publicity to do for the imminent publication of his latest book, The Blair Effect, a set of essays on New Labour's second term, which he has edited.
It's a busy schedule, but not, one suspects, out of the ordinary for Seldon, who's a man used to keeping plenty of balls in the air. In his eight years as headmaster of Brighton College, for example, he has written or edited 12 books, among them the weightiest biography yet of Tony Blair.
And he has found time to transform a faltering institution into the independent school of choice for parents on the south coast. "Parents like Brighton College to have a head who is regularly on television, or writing in the press, or publishing books, contributing to political or educational discussions or debates," he argues. "It means, for one thing, that we get more speakers down to the school who are involved in politics and public affairs. Good contacts. I think the school is enriched by that."
Soon, Seldon will face a new challenge when he takes the helm of Wellington College in Berkshire, one of the country's most prestigious, and unwieldy, public schools. When I was a Wellington College boy in the second half of the Nineties, the headmaster was Jonty Driver, a towering South African, aloof and intimidating, with a history in the anti-apartheid movement that naturally bred respect.
Seldon, who takes up the post in January, may lack Driver's physical stature, but his achievements are imposing. Though he has the disconcerting habit of answering questions with his eyes closed, or staring intently at the floor, Seldon's experience with journalists, and as a journalist himself, will stand him in good stead at Wellington, which has had its share of media attention in recent years.
Since a spectacular episode involving a Wellington boy filming himself and his unsuspecting girlfriend in flagrante in 2003, there has been at least one cannabis-related expulsion that made the papers, and a spate of tabloid tales about the school's bullying culture. "The school made some mistakes," Seldon admits. "But equally, I think the picture given of Wellington is unfair. Every single school in the country has bullying. Wellington was targeted and given a very distorted image, which wasn't balanced by the 99.9 per cent of things that happen at Wellington that are very positive: kids with great relationships with each other, who are very caring and responsible."
The head with the dubious honour of presiding over this period of ill-luck was Hugh Monro, who left the post this year and, says Seldon, "did an immense, and perhaps under-recognised, amount to make the school more civilised and humane".
It's true that what Seldon calls "episodes" happen in all schools. Even within the "drug-free zone" that Driver declared Wellington to be at every given opportunity during his tenure, the odd joint was smoked, and incidents of bullying occurred. But Wellington is still widely, if unfairly, regarded as a holding house for Sandhurst cadets and varsity rugby players.
The values it is seen to espouse most forcefully - of self-reliance and toughness, mental and/or physical - could also be regarded as euphemisms for a resigned attitude towards bullying. "I think the old-style Wellington, all-male, boarding, tough, not terribly cultured or academic, is all very 20th century," says Seldon. "There was much that was superlative about Wellington in the 19th and 20th centuries, but other parts fell behind. The new Wellington will capitalise on all the historic strengths of the school." And, one must infer, do away with the historic weaknesses.
One sure-fire way to drag a 19th-century boys' school kicking and screaming into the 21st is to go co-educational. Hence the recent announcement that, from September 2006, Wellington - which has taken sixth-form girls for 30 years - will become co-ed throughout. Seldon was instrumental in masterminding the move. Rumour on the old boys network has it that, when they heard the news, one group of sixth formers led a light-hearted protest by turning up to chapel in skirts.
"Going co-ed will enrich what goes on in the classroom, because whether you're talking about English or drama or even physics and mathematics, it is more stimulating to have female perspectives," Seldon argues. " Pastorally, it will make the atmosphere warmer and more enjoyable. It's going to benefit the arts enormously. It will become one of Britain's great co-ed sporting schools."
The first appointment Seldon has overseen is the new deputy headmistress, Lucy Pearson, who has been an England international cricketer for 10 years. "Going co-ed is what the school has been crying out for, and the staff are 100 per cent behind it."
nother benefit of taking girls will be an improvement in the school's academic performance, which has been lacklustre of late. "The school needs to be more academic, more focused, more purposeful," Seldon admits. "I don't want it to become an academic hothouse, but it's necessary for Wellington to be in the first division." (It currently languishes in the third.)
Seldon's belief in the merits of the International Baccalaureate are well known, and he's looking at offering it alongside A-levels at Wellington. But, he says, "it's wrong to impel children to study the IB if they don't want to take the set subjects. At 16, some children just want to give up maths or science or languages or the arts or humanities altogether, because they're fed up with them. For other children, I think the IB is a great option."
But he hasn't given up on A-levels. In fact, he recently sat one of the exams himself. "I wanted to find out what the experience was like, so I taught a class of philosophers and we did a module together for the AS. I set them the target of beating me, which they almost all did. Which, I think, shows two things: how clever they are, and how stupid I am..."
This is false modesty, but he has a serious point. "Teachers should sit the subjects that they teach. I think every teacher, every five years, should take a new exam. It's very important for teachers to sit an exam and have the experience that the children they're teaching have," he says. "It's also very enjoyable."
Even as headmaster of Wellington, daunting task that it is, Seldon plans to teach. "I love teaching," he says. "So much of being a headmaster is just very dull. The routine, administration, the policy statements, the daily grind of e-mails. Some of my fellow heads love it, it sets them alight with passion, but it kills me because there's no humanity in much of it. I need to be out and around teachers and pupils and parents."
Why, if he's enjoying himself so much, does Seldon want to leave Brighton College? Especially since, as he points out, Brighton's under-21s beat Wellington in the final of an independent schools rugby competition a few weeks ago.
Unlike the subject of his most recent book, Seldon feels eight years is quite long enough in any job. "I don't want to be one of those heads who stay on too long," he says. "I've made my contribution and the time has come for me to vamoose and let someone else take over. I feel I have rather run out of steam at Brighton." And to what does he attribute his success with the school? "I think bringing passion into every element of school life. Passion, enthusiasm, energy, belief and love."
Seldon has little time for teachers who lack his energy. "I cannot abide teachers who are lazy, who have lost their enthusiasm, bore children, or think the school owes them a living. The school does not owe any teacher a living, whether they've been there for one year or 40 years."
This is the sort of fighting talk that has earned him his reputation as a maverick in the independent sector, a guy who likes to stir things up, earning the ire of some fellow heads within the Headmasters' and Headmistresses' Conference (HMC).
But he is unapologetic. "The independent sector should be much more of an innovator than it is," he says. "I don't blame the schools or the heads. The disappointment is that the associations of independent schools haven't been more imaginative. They have been quite callow; inward-looking and defensive. They haven't played the kind of role in the education world that, say, teachers' unions have done - like the National Association of Head Teachers or the Association of Teachers and Lecturers. I think the sector could be much more upfront in setting the agenda on exams, on curriculums, on international links."
Seldon is insistent that not all independent school parents are stockbrokers earning six-figure salaries. "The vast majority are making a tremendous sacrifice. They are minicab drivers; they have corner shops; both parents are working; grandparents providing the fees; often remortgaging their homes; forgoing holidays abroad, all to pay for their child's education. And they're paying taxes for genuinely affluent parents to send their kids to selective state schools. This is terribly wrong, and the associations of independent schools haven't made the case for independent education strongly enough."
Under his command, he hopes Wellington will find a way to reflect the diversity of independent school parents and pupils. "A lot of independent schools provide bursaries," he says. "I didn't think the Government's assisted place scheme was good, because it demoralised the state sector. It was saying, in effect, 'You're not good enough to teach bright children.' But I'm very strongly in favour of independent schools providing bursary and scholarship support for children from non-privileged backgrounds to attend. I would dearly love to see Wellington substantially build up its bursary funds, to enable a far wider social range of children to attend."
To rub salt into the HMC's wounds, Seldon organises an annual education conference at Brighton College, whose pulling power (past guests include Charles Clarke, David Miliband and Chris Woodhead) often overshadows the HMC's own conference. This, no doubt, they find irksome. But Wellington needs a head willing to fight his, and the school's, corner. "I plan to hit the ground running when I arrive on 1 January. Get the governors and common room behind me, and just go for it.
"Wellington is going to become one very exciting school. I think it will be great, not just for Wellington people - I want it to make a real contribution to British education as well." Now, he looks me straight in the eye. "And I'm absolutely serious about that."
Anthony Seldon: a head for history
Worcester College, Oxford; London School of Economics; Kings College, London; Polytechnic of Central London.
Deputy headmaster of St Dunstan's College (1993-97); head of history and general studies at Tonbridge (1989-93); and head of politics and the sixth form (pastoral) at Whitgift School (1983-89).
Churchill's Indian Summer; The Thatcher Effect; Major: A Political Life; Number 10: The Illustrated History; The Blair Effect; and Blair, published in June 2004 and accompanied by the Channel 4 documentary In Search of Tony Blair.