Even though I went to Dulwich College, a school with a reputation for high academic achievement, I was never particularly gifted in that area. I wasn’t stupid - I was probably top of the bottom stream - but I was never going to set the world on fire with my prowess in exams.

During my economics A-level I was thrown out for falling asleep. I lost interest halfway through and nodded off. So, obviously, I failed it miserably. There again, I can’t help thinking that I got more out of Dulwich College than a lot of people who left with four good As at A-level.

For me, the strength of that school was that, even if you were rubbish at exams, you must be good at something and the job of the school was to find out what. So, I spent a lot of time playing rugby, training to be a swimmer and hours in the art department. I imagined that if I didn’t make it as an Olympic swimmer I would be a graphic artist, although, in the end, it turned out that I was better at acting.

Acting is in my genes. My father is the actor Peter Penry-Jones, my mother Angela Thorne (best known for playing Penelope Keith’s companion, Marjory Frobisher, in To the Manor Born). I grew up doing my homework backstage at various theatres and unlike some kids who claim they hate the notoriety of having actor parents, I was always incredibly proud of what they did. I just didn’t know for a while that I would follow in their footsteps.

I owe that first realisation, I think, to one of the teachers at Dulwich - Dr Jan Piggott, my English teacher. Perhaps because he knew my parents were actors, he imagined that I must be good at acting. He would get me to read in class and when I was 13, insisted I audition for a production of The Tempest.

At the time, all my mates were rugby players who didn’t think there was anything cool about acting, but Dr Piggott’s insistence wore me down and I got the part of Caliban. From that point there was no looking back. He put me on the road and Kim Eyre, another great teacher, saw to it that the journey continued.

Kim was my French teacher at Dulwich, but he also had a big interest in theatre. He directed Doctor Faustus at the school’s Edward Alleyn Theatre and head hunted me for the starring role.

Mind you, I was so bad at learning French vocabulary in his classes that he expressed doubts I’d ever be able to learn the mountain of lines needed.

Fortunately, the play was a success and Kim and I became the best of friends. Even now if I’m in a play he will come to see me and often the school will bring pupils along too.

I don’t remember any of the stuff that I learned academically. I couldn’t tell you about photosynthesis, for example, or the Battle of Hastings. But I could tell you about the first time I got on stage at the Edward Alleyn Theatre or the conversations I had over the years with Jan Piggott and Kim Eyre. Having teachers like that in your life, that to me is real education.

Rupert Penry-Jones, 36, trained at Bristol Old Vic and won the Ian Charleson Award for his Royal Shakespeare Company performance as Don Carlos. He won popular acclaim for his role as Adam Carter in the BBC series, Spooks. This Sunday he stars as Captain Wentworth in ITV’s adaptation of Jane Austen’s Persuasion. He will appear later this year in a new, as yet untitled, Stephen Poliakoff drama for the BBC.