British think tank the New Economics Foundation recently concluded that the Scottish are the happiest people in Britain. Which begs the question, why does this country produce so much grim and grisly crime fiction?

The relentlessly cold weather is an obvious place to start. The heavy rain and brooding clouds offer instant noir atmosphere – as does the harshness of the landscape. These are similar reasons as to why Scandinavian fiction is so popular. Like the Nordic people, the Scots do not do cosy. And they have a word for this – thrawn. It means obstinate, contrary. It’s a guiding principle in the Scottish psyche that if you tell them to do one thing, they’ll do another. And it’s an anti-authoritarian streak that makes for classic detective characters.

Scottish writers have penned some of world’s biggest bestsellers. There is even foreign academic interest in Scottish crime writing. A few years ago in Germany, the University of Gottingen hosted a conference on the subject. Papers included “Age of Devolution, Age of Retirement: John Rebus and Ageism” and “Crime Writing – Scotland’s Cultural Export”.

In Scotland in recent decades there has been much soul-searching about identity and the country’s place in Britain of the 21st century. Perhaps the crime novel has been an artful way of talking about the state of the nation.

But one thing is certain, it’s not only the Scots – ‘the happiest people in Britain’ – who are deriving great joy from the grimmest of ‘Tartan Noir’ crime fiction, but readers the world over.