Some years ago I met the Swedish crime writer Henning Mankell at the Savoy Hotel in London, where he was staying. A waitress came up to our table. ‘I think, Belinda,’ Mankell said to her suavely, ‘that I would like a glass or two of your red wine!’ Momentarily confused, Belinda asked Mankell to repeat his order. After she had gone, Mankell commented peevishly to me: ‘What’s the matter with her? Was there anybody at home? Hello?’ Clearly, the hoped-for flirtation with Belinda had not come off. More than just the top button of Mankell’s black shirt was undone.

Mankell could not have imagined how successful the Inspector Wallander mysteries would be when, 23 years ago, he published the first in the series. In his native Sweden, the series triumphed overnight; Mankell has now sold more than 30 million copies worldwide. His shambolic gumshoe Kurt Wallander remains one of the most impressive and credible creations in crime fiction today. Grumpy detectives are a staple of the genre, and Wallander is fabulously grumpy. He eats too much junk food; miserably divorced, he indulges in ever more gloomy talk of his (and humanity’s) demise.

Fans of the detective will be disappointed to learn that An Event in Autumn is to be Wallander’s final investigation. Mankell was diagnosed with cancer last January, and has reportedly grown weary of his creation. (Each week he receives letters addressed to Wallander; he has even been asked how Wallander might vote in an EU referendum.) The detective has become more famous than his creator.

In this 150-page novella, Wallander is increasingly forgetful, alcoholic and diabetic, yet he retains a degree of disabused integrity. Typically, the Sweden of An Event in Autumn is a country whose time has passed: behind the roseate flush of its social-democratic prosperity lies a deepening economic malaise and signs of racial tension. Wallander, the good cop, sad cop, is not in a party mood.

As with most of the Wallander mysteries, the plot unfolds in the fogbound flatlands of southern Sweden and is bleakly fixed in Baltic geography. The skeleton of a middle-aged woman turns up in the garden of a house which Wallander had wanted to buy for his retirement years. It emerges that Baltic refugees from the Estonian capital of Tallinn had occupied the house half a century ago. What is their connection (if any) to the skeleton? The novella appears to be distinctly Scandinavian in its gloom, with a supporting cast of accident-prone squad members, who blunder through the Swedish mists in search of a killer.

In his gruff way, Wallander is a lovable sleuth. Earlier in his police career, we learn, he had been very much exercised by questions of responsibility and justice. But now he is not so sure. With his stomach cramps, failing eyesight and Ikea furniture (still in its flatpacks), he looks forward hopefully to retirement. In a fascinating appendix, Mankell relates how Inspector Wallander’s debut, Faceless Killers (1991), was written in response to the social chaos abroad in Sweden in early 1989, when neo-Nazi attacks on immigrants were rife. The name ‘Wallander’, says Mankell, was plucked out of the telephone directory on 20 May of that year (he looked up the date in his diary).

In 1998, at the age of 50, Mankell married Ingmar Bergman’s daughter. He reveres the film-maker’s own desponding vision of life, and the admiration was mutual. (‘My father-in-law read everything I wrote,’ Mankell told me with pride). It was Eva Bergman who wrote the final full stop to the Wallander series. ‘I had written the last word, and I asked her to press the “full stop” key. She did so, and the story was finished.’ So there will be no more stories about the weight-gaining, drunk-driving, sternly pensive Inspector Wallander. The case is closed. Skål!