One morning he decided to open the window to liberalism and let his group write some play-scenes. He was looking over shoulders when he saw the line, "Have you shagged him yet?" He made a fuss, they complained that they needed to be realistic, he stood his ground.
They went into a huddle, then one of them called out: "Will you at least accept a bit of sex, sir?" And he said without a pause, "Depends who's offering it.."
I have to hold my hand up here and say that I enjoy coarseness, and it annoys me intensely when adults enthuse over someone like Billy Connolly, but turn white at the idea that the young might simply find pleasure in rudeness too, rather than be irredeemably corrupted by it.
It is also an issue of some importance to the teacher of English: where do you draw the line? If you encourage your pupils to respond to life in an honest way, sooner or later you are going to face the dilemma of "what goes?".
Much of what is turned out creatively in schools is dangerously safe - it avoids areas that might trouble the hierarchy. So the passive lesson is being reinforced that language is the tool of insincerity. Let's not fudge this. You are either concerned with meaning, and are prepared to go where it takes you: the other option is to involve yourself in the concealment of meaning. Art as the highest form of deceit, or self-deceit.
What can the teacher do? Box clever, I suppose is the only answer. People in all walks of life have to. If artists find themselves at odds with the public mood, they risk failure and financial loss. It's a risk they may take, though, if they believe strongly in their work.
So as a teacher, one can only give the issue its proper weight, take a deep breath, and prepare to defend it. But it's difficult. A lot of schools want their art meaningful enough to attract attention, but not too meaningful. They are concerned with lack of meaning.
I thought I had succeeded in disengaging myself from the horns of this dilemma when my writing life took shape, but I haven't. When I included my recent book The Willy Enlarging Elixir in schools publicity, I found my bookings for writers-in-school days declined.
"Read naughty books to boys, urges Blair", an Observer headline last summer read. "Authors today need some of the mischief of a Roald Dahl to keep children interested. I think he was one of the first who would write in a slightly naughty way, which makes books in-triguing and interesting."
But, regardless of what the PM says, I face the dilemma of either hiding my authorship of The Willy Enlarging Elixir in next year's leaflets, or going up-front again and losing more work. The irony is that when I am encouraged to read it the kids - particularly boys - can't wait to get their hands on it.
It involves an 11-year-old who is anxious about having to use communal showers when he goes to secondary school. He buys a pot of willy enlarging elixir from a friend.
"It had better work," he said.
"Ask my cousin," said Bertie. "He invented it. He's got a massive one now, damn near as big as an elephant's."
Doctor Rawalpindi comes to inspect the soreness Stewart is left with after using the stuff.
"Well, well, well, sir, and what have we got here?" he said, taking a little peep. "Oh dear, dear, native uprising in the corner of the empire. Very serious indeed sir. And what is the cause of the eruption?'"
They both look forlornly at the sore member.
Suddenly, Doctor Rawalpindi opens his bag and fumbles inside it. He hands Stewart a magnifying glass.
"See for yourself sir. I think we have first signs of development. Just there..."
Stewart scans the scene for himself. Yes. Doctor Rawalpindi is right. One tiny, curly little pubic hair, all on its own. His first one.
"Wow," said Stewart. "I never noticed. If only I hadn't've... Do you think it will survive?"
"One man alone defying the might of the British Empire," said Doctor Rawalpindi. He was beginning to get poetic. "Soon one will be many."
"You mean, it won't be long before.."
"It is inevitable sir, Independence Day very soon."
So, Tony, thank-you for your encouragement. There's a copy of 'The Willy Enlarging Elixir on its way to number 10 - present for the new arrival. I hope it doesn't offend. Happy Christmas.
Peter Hayden is the author of 'And Smith Must Score...', 'The Headmaster's Daughter', 'The Adventures of Stringy Simon' and other books for juniors and teens.