Ian Rankin at The Sunday Times Oxford Literary Festival

The sun’s shining, the blossom’s out and one of my favourite literary events of the year is underway.

The Oxford Literary Festival always attracts a galaxy of writing superstars and this year is no exception. Last night I hurried down to Christ Church to hear bestselling crime writer Ian Rankin in action. He was there to talk about The Impossible Dead, the second in his gripping new series featuring Inspector Malcolm Fox, a cop who investigates other cops. But he also spoke about Inspector Rebus’s retirement, his view that “a cop is a good tool for dissecting society” and his long abandoned PhD on the novels of Muriel Spark.

Like me, several members of the audience did a double-take when they walked into the grandly-named Master’s Garden Marquee. Ian Rankin was already ensconced onstage but instead of looking at notes he was busy filming us lot. The reason, he explained later on, was that Alan Yentob is featuring him in a forthcoming edition of BBC2’s Imagine series and has given him a video camera to capture his writing life. Considering that novelists spend most of their time shut away by themselves, Rankin reckoned that a film of him out and about in Oxford would make more interesting footage.

Tantalisingly, Rankin waved around the first draft of his new novel, due out in November. The contents are so top secret, he said, that he’s not even allowed to reveal the title yet. But he lessened the blow by giving us a different exclusive. He read an extract from a short story set in 1930s America, the first draft of which he’d finished the night before. “I loved doing it,” he said. “I didn’t realise what fun it was writing American PI (private investigator) stuff.”

Other revelations along the way included the fact that he chose the name Rebus because it means puzzle – after all, if Inspector Morse’s name is inspired by a code, why shouldn’t Rebus come from a puzzle? He revealed that his new protagonist, Malcolm Fox, is far more like him than Rebus. “I like writing about his family – his dad and his sister,” said Rankin. “And Fox is open to seeing Edinburgh as a beautiful city whereas Rebus sees it as a series of crime scenes.” Most telling of all, Rankin admitted that he feels a sense of unfinished business about characters like Rebus, his sidekick Siobhan and the notorious Edinburgh gangster Cafferty. Does that mean they might one day reappear in his work? Like millions of Rankin fans, I do hope so.