The Scottish government is exploring closer links with Nordic nations in the event of independence, reports have suggested. But just how similar is Scotland to its northern neighbours?

They don't make bridies in Bergen or Tunnock's Tea Cakes in Torsby.

Nor is Hakkebøf half as popular in Hamilton or Helensburgh as it is in Hvidovre.

But the North Sea which separates Scotland from Scandinavia could become slightly less of a divide if political leaders in Edinburgh have their way.

According to reports, strategists within the Scottish National Party (SNP) government have drawn up plans to shift the country's focus away from the UK and towards the Nordic countries if a referendum on independence is passed.

It's a plan which might appeal to those who support the SNP's drive for a sovereign Scotland, and might be expected to attract opposition from supporters of the union.

But regardless of contemporary politics, looking north reveals much about a little-discussed aspect of how the national character was forged.

In countries where it's dark half the year, you do tend to have a great tradition of storytelling Ian Rankin, Crime writer

The union with the rest of the UK may be more widely discussed in a political context, and Scotland's Gaelic and Celtic heritage might be widely celebrated. But the long history of Viking and Norse settlement in Scotland has left an indelible mark.

Scots words like bairn (child), midden (dump), muckle (large) and even kilt (from the verb kjalta, meaning "to fold") are derived from Old Norse. Places like Dingwall, Wick, Lerwick and Tinwald can all trace their etymology back to the same source.

This heritage is most visible during the Up Helly Aa fire festivals in Shetland, which culminate in the burning of a replica Viking galley.

But the cultural analogies persist in modern times, and not just in terms of Scottish shoppers visiting chains like H&M or Ikea.

Recent years have seen an upsurge in international interest in gloomy, gritty, Scandinavian crime fiction such as the Wallander series, Stieg Larsson's Millennium trilogy or the Danish TV series The Killing. Their success mirrors that of so-called "Tartan noir" writers like Ian Rankin, Val McDermid, Christopher Brookmyre and William McIlvanney, who have also used the detective genre to explore social themes.

According to Rankin, these very similar strands of fiction hint at something deep-rooted in national characteristics.

"In countries where it's dark half the year, you do tend to have a great tradition of storytelling," he says.

"Whenever I've met Scandinavian writers, we do share quite a dark sense of humour and a feeling that the world's messed up, we might as well laugh about it.

"Both sides tend to share quite a dark view of the human condition, and are certainly a long way from the Agatha Christie school of crime writing."

A shared Protestant tradition may account for this common interest in a genre which thrives on a pessimistic view of human nature. But as Rankin suggests, many of the cultural similarities could owe much to proximity.

An oft-repeated tale has Jo Grimond, former Liberal MP for Orkney and Shetland, being asked to give the name of his nearest rail station on a parliamentary expenses form, and writing "Bergen, Norway".

And for centuries there were political links across the North Sea. The first Viking raid on Iona is thought to have taken part in 794, and much of the Hebrides and Caithness would come under Norse rule. Orkney and Shetland continued to be earldoms under Norway until 1468.

Image caption Detective dramas in Scotland and Denmark are similarly downbeat

This settlement resulted in the Scandinavian-derived Norn language being spoken on Orkney and Shetland until the 18th Century, and influencing the Shetlandic and Orcadian dialects to this day.

But this Norse settlement did not, in the main, affect the central belt - the most populous, culturally dominant part of the country. This has meant the Nordic influence has been downplayed, according to Norwegian-born Dr Arne Kruse, senior lecturer in Scandinavian studies at the University of Edinburgh, who has lived in Scotland for 22 years.

In his view, however, this has led to many important potential areas of co-operation being downplayed.

"There are so many similarities, especially in terms of our relationship to nature - the oil, the fisheries, the fish farming, the renewables," he says. "There are so many parallels."

In particular, he says, Scotland's Presbyterian heritage mirrors Scandinavia's Lutheran tradition, lending both peoples an egalitarian suspicion of rank and a strong emphasis on the importance of education.

Image caption Horns feature prominently in the iconography of both sides (NB real Viking helmets did not normally have horns)

But while in recent decades, Scotland's preferences as expressed at the ballot box have arguably been closer to those of social-democratic Scandinavia than much of the UK, the economies of both sides are very different.

The Nordic countries have thrived on high-tech, high-skilled industries. By contrast, Scotland has placed far greater emphasis on services since its decline in heavy manufacturing.

The Scotsman columnist Lesley Riddoch set up the think tank Nordic Horizons to push for closer links between the Holyrood parliament and its northern neighbours.

She argues that regardless of whether Scotland opts for independence, it should seek to learn from these countries.

"It's like two cousins who have gone their own ways - only one of them still has his own hair, but they're still cousins," she says.

Look north Scandinavia: The three kingdoms of Denmark, Norway and Sweden

The three kingdoms of Denmark, Norway and Sweden Nordic countries: A region in Northern Europe and the North Atlantic which includes Denmark, Finland, Iceland, Norway and Sweden and the associated territories of the Faroe Islands, Greenland and Åland Enduring marks the Vikings left on Britain

"In many ways, Scotland is the southern, fertile end of the Nordic empire."

However, Riddoch accepts that the north will only ever be one influence on Scotland. Unsurprisingly, many Scots strongly identify with their Gaelic heritage. Estimates suggest that a third of Glasgow's population has family ties with Ireland.

Additionally, the fact that most opinion polls still show only a minority of Scottish voters favour independence is used by supporters of the union to argue that voters still value the link with the rest of the UK.

"It's true that Glasgow will be looking to Ireland as a Celtic nation whereas the east looks both to the Nordics and the low countries," Riddoch says. "But every nation has the same thing of looking two ways."

Indeed, Kruse argues that this mix of cultural influences is what sets the country apart from the more homogenous Nordic nations and, ultimately, makes Scotland Scottish.

"When I first came here I experienced a mosaic of cultures," he says. "That's what makes Scotland unique."