I was a monstrous child, truly appalling. At the age of 15, I was expelled from Uppingham School in Rutland for various misdemeanours and then from another public school (Paston in Norfolk) before graduating to Pucklechurch Prison for a three-month sentence. It’s a very long story, indeed. You can read about it in Moab is My Washpot, my autobiography, if you’re inclined to.

It was in Moab, too, that I described Uppingham in the Seventies, when I attended, as holding “a middle level of middle class, middle brow, middle England middledom.” But it did have many saving graces. Academically, I fared well and sat all my O-levels at the age of 13. That was how I came to find myself in the sixth form at the age of 14 and also how I came to meet Rory Stuart, the world’s most gifted teacher. I have so much to thank him for.

Rory Stuart, as his surname suggests, was descended from royalty and was, indeed, a prince among teachers. He was a shining beacon first at Uppingham and then, I gather, at other schools where he later taught, including Westminster and Cheltenham Ladies. Over the years, I’ve written and talked about him a lot and so I always get people from those schools sidling up to me at various events and saying: “I was taught by Rory Stuart too, you know.” And then we sort of grin, stand back and say: “Wow!” Because to have been taught by Rory Stuart is like being part of a very special club. Not everyone, sadly, can belong.

What was special about him? Well, let me compare Rory to, say, a sprinter. If you’re good at sprinting you probably run at club level, if you’re very good you maybe run for your county, if you’re great you run for your country and if you’re truly amazing you go to the Olympics and bring back gold. In teaching terms, that was Rory Stuart. Just so much better than the competition ... by miles.

Though he read classics at Cambridge - the university I later went to myself, after I had sorted myself out - he taught English literature and with such contagious passion that it was impossible not to respond to him. It was as if every single line of poetry, or dialogue in a play, or chapter of a novel was the most thrilling discovery he’d ever made. There’d be a huge smile on his face and he’d explain his emotional response in such an inspiring way. On top of this, he valued whatever anyone else contributed. Nobody’s opinion was invalid and even if it was dumb or cliche ridden, he would find a way of honouring it.

For Rory everything was a feast of the senses. So he could make writing come alive in even the most dimwitted, bone headed, rugby playing breasts.

In 2005 I wrote the book The Ode Less Travelled, a kind of layman’s guide to understanding poetry, which I dedicated to him. I wrote it because, thanks in very great part to Rory, I don’t just love the form but also the idea of teaching others about poetry and communicating my own enthusiasm in the same way that he communicated his enthusiasm to me.

Being taught by Rory made me venerate not just literature but the art of teaching itself. As a result, I think there is an immense pedagogical strain in me. Teaching is, in a sense, my thwarted vocation.

Before going to Cambridge to study English literature I offered my services at a North Yorkshire prep school and taught every subject they would let me loose on. I have probably never been happier. But I also learned that teaching requires the most astonishing levels of energy. You go in and give it your all and then you think: “Christ. It’s only morning break” and you’re exhausted and thinking: “I’ve got to do that five more times today.” How Rory kept up his energy for class after class astonishes me. But, exhausting as young people can be, he always had more beneath the bonnet than an entire class of teenagers.

Sadly for the teaching profession, he changed course and is now an expert in gardening. He wrote Reflections from a Garden, with Susan Hill, the novelist, and now lives in an idyll in Tuscany.

We have stayed in touch. We write and see each other when we can. He always tells me off for talking and writing about him because, on top of it all, he is a modest man, embarrassed at being venerated. Apologies again, then, to him. But I do stand by everything I have said.

Stephen Fry, 50, is an actor, comedian, writer, director, TV host, documentary maker and raconteur. His new series of Kingdom will be screened weekly on ITV1 from January 13. He was talking to Daphne Lockyer.