"From the age of seven to 13, I went to prep school, where I was beaten a great deal," says Stephen Fry. "I think in my last year, I was probably beaten every day because I was a very bad boy." Thirty-five years on, the "actor, writer and something", is about to appear as Dr Thomas Arnold, the 19th-century Rugby School headmaster in a television dramatisation of Tom Brown's Schooldays. It is this latest role that has brought Fry's memories of his own time at boarding school flooding back. They were not, it is clear, the happiest days of his life. Not that he's complaining.
"People might think, 'Oh my God, no wonder Stephen Fry is such a completely screwed-up individual!'," he laughs, acknowledging that his life since has not been without its dramas. "But I don't know whether that's true, as I am fairly sure I would have been screwed-up wherever I had been."
Fry is holding court at a chic central-London private-members' club at the end of the Tom Brown's Schooldays shoot. Done up in a suave dark suit that screams "expensive", he looks completely at home in the effortless "in-crowd" ambience of the club. He is just as charming, cultured and civilised as one might expect.
Delving into his personal treasure-trove of schoolboy memories, the 47-year-old actor emerges with one gem after another. "I don't think that I suffered any bullying at all," he muses. "I had this marvellous strategy, which was a perfect way of stopping anyone who started hitting me. I would say, 'stop it, you'll give me an erection!' Worked every time!"
It is a trick which could have been of use to the boys portrayed in Tom Brown's Schooldays. Tom Brown, who arrives at Rugby at the same time as Dr Arnold, is immediately plunged into the school's culture of endemic abuse. Soon after coming to the place, he is asked to take some hot water to a senior boy. Carrying a bowl along a corridor, Tom has his first meeting with Rugby's resident cad, Flashman. It is not a pleasant encounter.
When Tom courteously but firmly refuses to give Flashman the hot water, the school bully roars with laughter, like a villain who has 007 captured in his lair. Smiling menacingly - he's always at his most dangerous when he's smiling - the bully then pours the contents of the bowl over the head of the hapless new bug.
"You dare to disobey me, you execrable little turd?," Flashman sneers. "I've just made a rather splendid decision, Brown. I've decided I'm going to make your time here a complete and utter misery."
Flashman keeps his promise, ensuring that Tom suffers from several truly horrific acts of cruelty. Being violently tossed up and down in a blanket or roasted over an open fire, anyone? Evidently, Flashman is not the sort of lad you would ever want to accompany on a long walking holiday through the Cotswolds.
Fry shows just how much authority Dr Arnold requires when he pitches up at Rugby at the beginning of the drama. The place is like the Bronx on a bad night. "The school Thomas Arnold came to was in a state of anarchy," explains Suzan Harrison, the producer of the drama series. "There was no pastoral care; masters left the school at the end of the afternoon, leaving the boys to their own devices, drinking, gambling, whoring and bullying."
It is this idea of bullying that makes the drama resonate for modern audiences. "Bullying is an eternal theme," declares David Moore, the director of Tom Brown's Schooldays. "Grange Hill has done bullying to death, and it also crops up in the Harry Potter novels - look at the force of the character of Harry's rival, Malfoy.
"But those stories are just picking up on the archetype of Tom Brown's Schooldays. It still has power because people never change. We never learn from bullying or wars. War is just a more grand form of bullying."
It was not bullying, however, that did for Fry's schooldays. In the end, Fry recalls, he left boarding school because of "three words: 'You are expelled.'" Fry, who attended Uppingham after prep school, was hardly a model pupil. "I went to places where you weren't allowed to go, and I shoplifted, which was the final straw. I was not a good example as a modern schoolboy. I was kicked out of Uppingham and of another school. I was a terrible teenager. No school could mould me."
But Fry's expulsion did not spell the end of his own schooldays. Next time round, though, he was on the other side of the fence. In his "gap year", the actor found himself back at prep school - as a master. "Instead of putting on a backpack, I taught at a prep school before going to university. I remember I was on duty one evening after lights out, and there was a lot of noise coming from the dormitory. I told them to shut up, but they made more and more noise, and eventually I said: 'Right, the next person I hear a squeak from will get the slipper' - which was the prep school's particular instrument of corporal punishment.
"Unfortunately, I heard a squeak, and I said: 'Right, Phillips, dressing gown and slippers, down into the staff room.' So he came trembling down into the staff room. I picked up this slipper, and I went 'smack' on the back of my own hand. I said: 'now let that be a lesson to you'. He looked at me with extremely questioning eyes and asked: 'Is that it?"'So why could Fry not emulate Dr Arnold and beat the errant pupil? "I just could not hit a child," reveals the actor. "It is not because I have any great moral qualities. I just think I am of a generation that has seen this change. When I was a boy, it was absolutely unquestioned that children were punished with the cane or slipper. But now no one questions that this is an absolute wrong. For thousands of years, all Western cultures, as far as I can tell, have beaten children. It has just been the norm, and it is very interesting that now it is the absolute opposite."
Fry is steeped in the culture of the Victorian public school system, and that knowledge stood him in very good stead for the role of Dr Arnold. In Ashley Pharoah's drama, which was filmed in part at the real Rugby, Fry brings a sense of gravitas (and a neat set of sideburns) to the role.
The actor reckons that Thomas Hughes's visionary 1857 novel is the well-spring of literature's current fascination with boarding school. "This Rugby is the original school from which all others are descended," Fry observes. "It is the prototype for the Harry Potter stories. The school at first hovers between good and evil, and gradually Tom shows that through his own bravery he can become someone you can believe in. Yes, it's essentially the Harry Potter story!"
But for all the superficial glamour of the costumes and the "jolly japes" of Harry Potter and Tom Brown, the actors in this drama have certainly not been won over to the concept of boarding schools in general. For Julian Wadham (who plays Squire Brown, Tom's good-hearted father) who himself went to public school, the depiction of the harshness of boarding-school life rings all too true.
"It was all about the survival of the fittest," sighs the actor. "I still remember the pain of standing as an eight-year-old boy in a grey suit on the platform at Victoria Station waiting for the train to take me away to boarding school.
"I also remember my brother's first letter home from boarding school as an eight-year-old: 'Dear Mr and Mrs Wadham, on one side I sleep next to McConkey, and on the other side I sleep next to a wall.' Heartbreaking. Would I ever have sent my own children to boarding school?" Wadham shakes his head vigorously. "No, I could never have done that to them."
Fry may be a strong contender for Renaissance Man of the last few years, but he certainly went through some dark days as a teenager. He was convicted of credit card fraud and sentenced to three months at Pucklechurch Prison. Now he likens boarding school to jail. "They are almost exactly identical, institutions where people are brought together in one place. All the same gender, they develop a corporate spirit and a group dynamic, which is the same whether you are talking about a public school, a prison, or the army for that matter." Not exactly a ringing endorsement.
'Tom Brown's Schooldays' is on ITV1 on New Year's Day at 9pm