Speaking at the Chiltern Kills crime fiction festival, he added:  “It’s not dark and gritty, people are looking for something that is more comforting

“The world is explained to them, everything will eventually make sense, and although things will be shaken up, normality will resume because the crime has been resolved.

“That’s happening a lot just now in television and in books.”

Sir Ian has sold more than 35 million copies of his Inspector Rebus books, which are typically set in the gritty underworld of Edinburgh, where the hard-drinking hero tackles murder, rape, prostitution, child sexual abuse, and modern slavery.

While his books have proven popular, recent years have seen the rise of Osman as a leading crime writer after the runaway success of The Thursday Murder Club, a book about retirement home residents who solve murders. It sold more than 10 million copies.

The Rev Richard Coles has produced his own set of mysteries featuring an Anglican rector as the hero.

‘A hard time of it’

Sir Ian has said the proliferation of non-uniformed protagonists reflects an increasing public distrust of the police: “The poor old police detective is having a hard time of it, because the public doesn’t necessarily think of the police as the good guys anymore.

“On the back of what happened in America with Black Lives Matter and what happened with the Met in London specifically.”

He added:  “I think a lot of younger writers, new writers in the genre, are thinking, I don’t want a cop as my main character, who can I have that is more attractive to the reader?

“It could be people in a retirement home, pathologists, psychologists, people who make crossword puzzles for a living, it could be anyone but not perhaps a cop.”

Sir Ian has stuck with his own fictional detective, and his latest novel, Midnight and Blue, sees Rebus jailed and operating inside prison. The author visited HMP Edinburgh as part of his research.

The book is the 25th Rebus novel, the first being Knots and Crosses, released in 1987.