Brian Martin is an Oxford man through and through. After studying English at Hertford College, he spent 40 years teaching literature at Magdalen College School and Oxford University before retiring in 2001. Now at the age of 68, he has set his first novel here.

North is set in a boys' school whose location is very similar to Magdalen. Local places such as The Quod Bar and Caf Coco feature, too. The novel is narrated in the first person by an unnamed middle-aged teacher. He tells of a predatory Anglo-American sixth former known simply as North, who initiates relationships with first a female, then a male teacher. Beautiful, charismatic and cold-hearted, North is the catalyst for a maelstrom of sexually anarchic behaviour which has far-reaching, destructive consequences.

This is a book that deserves two readings, the first time to get the story as told by the narrator, the second to understand his psyche and motivations. He would have us believe that he is a detached observer of North in his amoral game of love, but one starts to wonder whether this is really so.

There are meaty themes here: the nature of evil and the way Cupid's arrow can make fools of supposedly rational people. The author said: "I'm interested in what Milton is interested in the problem of evil, what that is like and how it manifests itself in real life. I certainly believe that it can present itself attractively. This is the idea of Lucifer falling, becoming Satan, but not losing angelic qualities. He's still very attractive and seductive and that's the way that evil presents itself to us, as being attractive."

He sees the book as a psychological drama. "I'm interested in the way that people behave towards one another, and certainly in closed communities, which often reflect the wider world," he said. He has very strong views about inappropriate relations between pupils and teachers. "It just won't do. It's not the role of the teacher to indulge in sexual relationships with pupils." Nevertheless, he recognises that it does goes on. "You only have to open your newspaper to see it, and therefore it has to be written about."

The reason for the scholastic framework is quite simple. "Like all novelists, you use patterns from your own experience but then you embroider them, use your imagination, make up as you go along." Given that the setting so closely mirrors Magdalen, however, I asked if the book had been controversial.

"Not as far as I know," he replied. "One person has said: 'Oh you're writing about me.' I said: Certainly not.' Other people have said: There are some contenders for North, you know.' And I say: Really, who are these?' There are about four so far. Most surprising. Absolutely entirely wrong. He's totally, totally fictional."

North reminded me in part of a character in Mikhail Bulgakov's The Master and Margarita so I asked if that book had been an influence.

"Not consciously, but it's certainly a book that I much admire," he replied. "So many people say that they see the influence of other writers in North." They include, among others, C. P. Snow, Iris Murdoch and Donna Tartt. "When you get to my age, you've read all these things and they've been working away inside you and perhaps come out in some way or other." He thinks it's quite amusing and gives a bark of laughter as he adds: "Now it's Bulgakov to add to the list." After years of analysing other people's work, he seems to be enjoying the attention that North is receiving.

He loved teaching at Magdalen. "I just enjoyed being with people, talking to them, verbally fencing, showing people what I enjoyed in literature and hoping that they might enjoy it as well, but realising that they might not, they might enjoy something different."

Even so, he was ready to retire as he considers the nature of teaching has changed and he disliked the increasing bureaucracy. "You were regarded as a professional when I went into the teaching profession, but you're not nowadays," he said. "Individually, you cannot stand as a professional. You are answerable within the unit of teaching." He believes that creativity is stifled by the centralisation of control from government down through layers to the individual teachers.

Although he's written academic books, North is his first novel. He had never thought about writing them before, firstly because he didn't have the time and secondly because it didn't cross his mind that he could. "I never thought I'd have the imagination," he said. Well, he not only does, but he forces you, the reader, to be imaginative, too, since the ending is somewhat ambiguous. After re-reading I thought I'd worked it out and told him my conclusions. He smiled with an inscrutable twinkle and said: "You might be right."

North is published by Macmillan at £12.99.