The teacher who had the most influence on me was my history teacher at Temple Moor Grammar School in Leeds, a chap called Dave Simmonds. He had just left King’s College, London, and it was his first teaching post. First impressions were hardly propitious, although he was only 22. Even in Leeds in the 1960s he was completely out of fashion; he wore Hush Puppies, Brylcreemed his hair and always had chalk on his backside. Yet as he wasn’t so different in age from us, we had a degree of empathy and rapport, and he won our confidence early on.

Dave joined Temple Moor in 1968 at the beginning of my O-level course. It was a state grammar school for boys, a typical 1950s building with an all-pervasive smell of floor polish, which it retains to this day. The rules were quite strict and you had to wear uniform even in the sixth form. The academic standard was high and I worked hard in the subjects I was interested in, particularly history and English.

You were treated as a juvenile until the sixth form, at which point you felt, especially with Dave Simmonds, that you were on more of an equal footing. If he came into the local pub he would join us for a drink. He didn’t confine us to the dried dust of history; he would often prompt informal discussions about current events.

And he had a curiosity about the world - we would talk about cinema, theatre, art, football or politics. Monty Python was a big subject in those days, as was the controversial film, Straw Dogs, and I clearly remember discussing it in detail. Dave was pretty easy going although from time to time he would assert himself, but not for long. He had a very dry sense of humour and he took the rise out of us just as we took the rise out of him.

Dave brought a vibrancy to the subject; he wasn’t just going through the motions, teaching by rote. I enjoyed the Tudors enormously and often debated with Dave the importance of Henry VII versus Henry VIII. He argued that Henry VIII was a more significant monarch with his reformation of the monasteries and the break-up of the Catholic church. However, I felt that Henry VII stabilised the monarchy and defeated the power of the over-mighty barons, laying a framework for the future. I would still argue that, although less flamboyant, Henry VII was the more effective monarch.

When I went back in 1993 to open a new wing, the headmaster pointed out that I once got seven detentions in a week, so I obviously went through a period of being quite rebellious. There came a point when we all felt that the regime was too strict. During general studies we talked about revolutionaries such as Mao Tse Tung and Che Guevara.

Everyone in the sixth form collectively decided not to apply to Oxbridge because we felt that it was too elitist. We went for trendier universities and I chose Sussex. I was always interested in history and English and it was very much a toss-up between the two. I don’t quite know why, but I thought that in gaining an understanding of how the present relates to the past, history was slightly more analytical. Journalism was among my ambitions, although my father was quite keen for me to go into his office materials and picture framing business. But I wanted to do something outside the academic world. I’ve got twitching-curtains syndrome - wanting to know what’s going on behind the nets.

When Diana, Her True Story came out in 1992, Dave was approached by newspapers writing coruscating profiles of me. He very kindly said I was one of the best history students he’s ever had. He now teaches history at Allerton High School, Leeds. I saw him again a few years ago and he hadn’t changed a lot, still wearing Hush Puppies. And I swear he had chalk on his corduroy jacket.

Andrew Morton, 45, is a writer, broadcaster and biographer. His best known biographies include ‘Diana: Her True Story’ , ‘Diana: In Her Own Words’, ‘Moi: The Making of an African Statesman’ and ‘Monica’s Story’. He lives in London with his wife and two teenage daughters. He was talking to Judy Parkinson