On the dark winter’s day when the United Kingdom formally left the European Union a Twitter user calling himself Fred posted a picture of British flags fluttering over some rocks near Gretna.

There had, reported the anonymous account, been a “stooshie” at the Old Acquaintance Cairn, the mock megalithic structure put up by opponents of independence in the run-up to the 2014 referendum just 30 feet from Scotland’s border with England.

Fred - his avatar is a smiling, bearded man in a Union Jack kilt - was declaring victory over Scottish nationalists who wanted to leave pebbles painted with saltires and Yes logos at the site. “The Nats turned up to desecrate it,” said Fred, “unfortunately unionists got there first.”

The cairn stooshie of January 31, 2020, was a minor stand-off between flaggy activists - Fred claimed police were at the scene - and did not even make news at the time.

But it is, reckons archeologist Kenneth Brophy, worth thinking about.

Why? Because ethnic nationalism, whether British or Scottish, is not just about blood and soil, but also about stones, even those left in the ground by people who lived long before there were such things as countries or states.

The cairn, Brophy writes in a new paper published last month, is an “egregious” example of the political abuse of prehistory, of an assertion that such structures were somehow typical of an ancient race of “Britons” that simply never existed.

In a decade of ever more tribalistic constitutional politics in Scotland and the rest of the UK, rival nationalists increasingly look to pre-history and the dark ages to find legitimacy for their causes.

And they do so even when their ancient nations are as fake as the Gretna cairn.

Last week this newspaper looked at the modern historical myths polluting Scottish politics, especially online; lies about Churchill sending tanks to put down Clydeside workers, the SNP supporting Hitler or Scots being ‘white slaves’ in the Caribbean.

Historians on social and mainstream media are fighting a rearguard action against toxic “mishistory”.

So are archeologists. Brophy is one of them.

His paper, “Hands across the Border?

Prehistory, Cairns and Scotland’s 2014 Independence Referendum” which was published in a new book on the archeology of borderlands, focuses on Gretna’s new attraction and its enduring appeal - and not least its clear ‘nationalisation” of a past before nations.

The monument was erected from stones from around the current century-old UK and was the brainchild of one-time centrist Conservative leadership candidate, the then Penrith MP Rory Stewart.

“The choice of a prehistoric-style cairn is for me the most intriguing aspect of this project,” wrote Brophy. “Why a cairn, and why in this form? Stewart noted that these ‘stone structures have been created by Britons since ancient times, as the physical expression of the values of the community’.

“These claims are problematic, as cairns are such ubiquitous aspects of the Neolithic (and indeed Bronze Age) of large swathes of Europe that they would appear to have little relevance to arguments about northern British unity. "Prehistoric cairns were not built by ‘Britons’ in the modern sense of this word.”

In fact, the cairn is modelled on a structure only found in the Highlands.

In recent years there has been an explosion of populist and popular claims that archeology shows there is - and, more importantly, always has been - a single British people.

A television show about new digs in Orkney fronted by presenter Neil Oliver - an outspoken unionist - described the northern islands as “capital of ancient Britain”.

On social media some British unionists have even adopted the Picts - a dark ages culture about which little is known - as proto-Britons.

Why? The Picts may have spoken a language like Welsh or the Brythonic dialects of what is now England before the Anglo-Saxon invasions of the sixth and seventh centuries of the common era.

The message: Scotland is Britain and always has been.

In this distorted version of history, the seas around the British Isles are moats, not motorways.

The reality of the ebbs and flows of cultures and languages across the waters lapping Britain are of little interest for those of a nationalist world view. This chauvinism has modern-day victims too: the remains tens of thousands of Gaelic speakers whose language does not fit in to the invented narrative.

But fake ancient history is not just for British nationalists.

Scottish ones, as Brophy stresses in his paper, frequently reference Hadrian’s Wall as they try to establish longevity for their nation.

The wall is routinely used as a synonym for the Scottish border even though it is now fully inside England, Brophy said.

Indeed, the structure marks just one line the Romans drew across the island of Britain; another was further north between the Clyde and the Forth. But that doesn’t stop the myth-making.

There is nothing new about politicians - including racist or nationalist ones - making up stories about distant and mysterious pasts.

Indeed, ancient Rome had its own stories of how it came to be.

Archeology has its own dark past. For much of the 19th and 20th century some archeologists had what now looks like a sinister objective: legitimising white supremacy.

The Germans portrayed in the Indiana Jones movies hunting for ancient evidence of the Aryan race were fictional. But they had a real inspiration, the Nazi archeology research institute, the Ahnenerbe Lorna Richardson, of the University of East Anglia, reckons some of these themes are back in the mainstream.

She said: “As Britain moves away from the European Union, and populism re-grows across Europe and North America, Far Right narratives of biologically determinist notions of nationhood and heritage and white supremacy are relocating to mainstream culture.

“Archaeology has a long historical relationship with nationalism and has never been immune to politicisation. The reinterpretation and manipulation of the past by the Far Right is not new.”

Indeed, for Richardson, archeology grew alongside nation-states in the 19th century “acting as a buttress to national cohesion, to support claims to territory, and act as a mirror for present-day identity”.

Scotland and England both emerged from the dark ages as states if not yet nations. The far-right has latched on to symbolism from this period. The extremist English Defence League has been patrolling the channel with a boat named after Alfred the Great, the king believed to have united England for the first time. Celtic and Germanic images from the British Isles and elsewhere in Europe are often used by extremists, including in the new world.

Richardson, however, stressed the power of social media to push nationalist narratives - including those that endanger lives.

Twitter, Facebook and other platforms, she said, have “enabled the spread of these myths and biases to a wider international audience, many of whom are unable to critically engage with this material and identify ideological bias”.

“The mythologising of ancestry and landscape, or ‘belonging’ invokes strong emotions, and this is hard to challenge with science and nuance in the post-truth era.

She added: “The imaginary past of neo-Nazi identitarian groups exploits symbols, sites and characters from history, be they runes, battle-axes, or even Stonehenge.

“The fact that these are largely fabrications does not seem to matter.

“These mythical pasts are far from harmless, and archaeologists cannot continue to dismiss these claims of superior ancient genes, victorious past migrations by warlike ancestors, and online battles for indigeneity.”

Brophy echoes these concerns. He fears Rory Stewart’s fake cairn could become a flashpoint for rival groups whose fake histories are incompatible.

The ‘stooshie’ at Gretna in January was just one of a number of minor incidents at the site, which has been vandalised. This monument - built on an abandoned caravan site just six years ago - is already subject to both veneration and hate, as Fred’s tweet about desecration suggests.

“The conflation of ancient and modern identities and motivations represented by the Auld Acquaintance cairn is problematic, precisely because it suggests that we should live our lives today, define our identities, vote in a democratic process, according to things that happened 500, 2000, even 5000 years ago,” wrote Brophy. “At a time when prehistoric monuments have become a focus for English nationalism, Brexit-related electioneering and Neo-Nazi ceremonies we should be vigilant about the uses and abuses of a cairn that was built to support British nationalism and is from time to time appropriated by Scottish nationalists.”

“Perhaps,’ the archeologist concluded, “it would be better that Auld Acquaintance be forgot.”