Goodnight Mister Tom, Grand Opera House, York, until March 2

At the heart of Michelle’s novel – a moving story of an abused London boy blossoming under the care of a village elder when evacuated to the Dorset countryside in wartime – is a passionate belief in the power of education, art and theatre.

“My parents came from totally different backgrounds and would never have met but for the war.

“My mother, who was a nurse in wartime, was the middle-class daughter of a clergyman and went to private school,” she says.

“My father joined the Navy at 15. He only had shoes at school and was the eldest of nine children, but he had a roaring IQ – and after the war became a barrister. It was only later that I understood what they went through.”

By the age of ten, Michelle’s father had completed all the education that should have taken him to the school-leaving age of 14. While in the Navy, he passed all the exams necessary to go straight to teacher-training college after the war. In other words, he kept defying prescribed expectations.

“One of the sayings we were brought up with – and you know how your parents repeat things! – was my father saying ‘there are geniuses sweeping the roads’,” says Michelle, above.

“So it’s not what you have but what you are – and as in my father’s case, what you did with what you were given.”

Michelle believes responsibility for nurturing a child’s gifts lies not only with parents. “It’s also up to other adults to do that. I don’t believe it’s just up to parents. A different teacher can see something completely different in a child,” she says.

“What I worry about now, though, is our anally retentive education system. How can you box children together when they develop at different times?”

As for art and theatre, “the arts are good for your mental health,” suggests Michelle. “When my sons get up, straightaway they’re writing and drawing.”

• Goodnight Mister Tom runs at Grand Opera House, York, until Saturday. Box office: 0844 871 3024 or atgtickets.com/york