He was a modest man, not flashy or a firebrand. He was very quiet and calm but he had a twinkle in his eye. Instead of being in your face he was very laid back, and made you come to him. I'm sure it was deceptive. He wasn't passive, because we were learning all the time and he created an atmosphere for learning.
I came from a very working class background - we lived in a prefab in Kilburn, north London. I thought a public school would be like the books I had read - full of people in tweed jackets. But I loved school. University College was one of the first liberal day schools, there was a relaxed atmosphere and they drew on your imagination as much as your ability.
The fees were a bit of a problem. I had a rich godfather who paid for my early education, but then there was a family argument. My father, who was a glass salesman didn't want to take me out of the school, so he worked hard putting in all the hours so I could carry on going there.
It was more like being at university than school - in the classroom everything was open for debate and discussion. In modern parlance Mr McGregor's classes were "quality time". Whatever the subject he would let you make connections to your own world - you could talk about anything.
I spent a lot of time hanging around in coffee bars trying to be like Jean Paul Sartre - it wasn't very productive but it was the early Sixties, and that was the thing to do. Mr McGregor would ask us what was so interesting that we could spend all our spare time drinking coffee and talking. He would ask us if we really thought these conversations were beneficial. But he wasn't being sarcastic - it wasn't in him.
One of the most important things he did was make us read poetry and plays out loud rather than ask us "what does it mean?" or "what are the themes?" It made the language feel like it was part of us.
I used to like D H Lawrence. Although he is despised now, as an adolescent boy I thought he was great. But the most thrilling classroom reading we did was Macbeth. Mr McGregor told us that just because it was Shakespeare, you didn't have to put on a funny voice.
History and English came together in his lessons. We would be reading something and he would say: "Here is a society, here is a community - how did they get here?" He taught us that things aren't all divided up into compartments - everything belongs, everything pertains. Later, as an actor, I found that very useful.
We could never work out if Mr McGregor was religious, but he had a strong moral code. Looking back I can see what the school was trying to do. Whether you became a lawyer or a doctor or an actor you would remember that you were part of a society and you had a responsibility to other people. When I started going out with girls at the age of 16 or 17, their parents always used to say how nice all the boys from University College School were.
I went up to Manchester University to do general arts. But when I got there I saw the drama department was short of a couple of male students. So I went along and they asked: "Do you know anything about restoration drama?" I said: "No... but I'd love to find out." So I did a piece from A Winter's Tale for my audition and I changed courses - to my parents' horror. They imagined drama students spent all day sitting around dressed in black, smoking cigarettes.
I am still in contact with Mr McGregor - he comes to see me in the theatre now and again. As an actor you have to be a conduit for other people's words and that was a gift he gave me. Practically every student who came into contact with him, whatever they did afterwards, holds him in this kind of affection. I was fortunate to have such a wonderful teacher.
Paul Moriarty is best known for playing George Palmer in BBC1's 'EastEnders'. He also spent six years with the Royal Shakespeare Company and seven years with the Royal National Theatre, and has appeared in more than 100 television series.He was talking to Harvey McGavin