The life-changing encounter in the confessional is such a staple of films, plays and books that Sarah Dunant enters a plea of mitigation before recalling her own. “It’s a story”, she says, “that suggests I became a novelist too young and made this up, but I remember it completely accurately, right down to the priest’s accent.”

It was 1965 and she was 15, the clever, questioning daughter of a Catholic mother, “French in origin, but out of the Indian Raj”, and a Welsh agnostic father. Sarah and her brother were being raised in the faith in their parish in Shepherd’s Bush, west London, but she had won a place at a prestigious, non-Catholic grammar school.