I was written off as being a waste of space at junior school and told I would never pass my 11-plus. That negative way of thinking didn’t help, but I passed. I could have gone to any grammar school in Liverpool, but my mum said, “You’ll never get up in the morning - there’s no point sending you on a bus.” She chose my school based on proximity.

My favourite teacher at Cardinal Allen grammar school was a guy called Paul Capstick. He was my English teacher and also my form teacher in fourth and fifth year. I liked him because he was always ready to listen. One time, I got into a fight with a bigger kid, and instead of straight away giving me a detention or the strap, Mr Capstick said, “Sit down. Okay, what happened?”

He was skinny and going bald, and had a strange articulation of the wrist. His hands were bent back towards the body, in a non-threatening way. He had very long limbs but wasn’t actually awkward, just all jointy.

Mr Capstick encouraged me to read. Other teachers taught Shakespeare by passing the book around: I would read the first five lines, and somebody else would read the next five lines, without any real understanding. You can’t learn Hamlet that way. But Mr Capstick introduced us to plays by the likes of D.H. Lawrence: literature that was more accessible, language we could understand, so reading it out loud in class was very beneficial to me.

Long after I left school, Paul Capstick ended up living in the street where I lived. My mum said, “Guess who lives in the square?” I thought this was very odd - I’d been brought up to think that teachers were somehow a cut above. I figured, they’re not paying this guy enough if he has to live in my street.

We also had a teacher called Joe Hartley who directed the school plays. As it was a boys’ school, only the choir boys (who were pretty enough to dress up as girls) and the sixth formers ever got to act. No one else had a chance to get involved. But one day I was there during rehearsals, just messing around, and Mr Hartley said, “If you think you can do any better, get up here right now.” So I did. The play was Nikolai Gogol’s The Government Inspector, and that’s how I became an actor.

There were a few teachers at Cardinal Allen who still wore the old-fashioned schoolmaster gowns. One of my old form teachers was vaguely on my mind when I was preparing for the role of Professor Quirrell in Harry Potter and the Philosopher’s Stone. I remembered the way his robes would fly when he threw things at us, or when he brought the ruler down on my knuckles with a swoosh. The way in which he moved was the only other reference point I had for my character. Who else do I know who wears robes Ian Hart is an award-winning actor. He played Professor Quirrell in Harry Potter and the Philosopher’s Stone. He was talking to Mary McCarney