Nicola Sturgeon strode purposefully towards the lectern after her latest push for Scottish independence was thwarted.

The First Minister branded the UK Supreme Court ruling that the Scottish parliament could not unilaterally hold another referendum without Westminster approval “outright democracy denial”.

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For too long, she argued, Scotland had endured an unsustainable democratic deficit in a union where ultimate power remains in Westminster, even in devolved policy areas.

The judgement reaffirmed her primary grievance: the illusion of Scottish self-determination.

“What I’m not prepared to do is to allow Scottish democracy to be a prisoner of Westminster, which effectively means that Scottish democracy doesn’t exist,” she said.

The independence movement has put the relationship between London and Edinburgh under a renewed strain not seen since the days of Margaret Thatcher.

The central tenet of Thatcherism to roll back the frontiers of the state at the expense of industry had disastrous ramifications in Scotland as London boomed following the sudden deregulation of the financial markets.

Margaret Thatcher
Margaret Thatcher remains a divisive figure in Scotland

The testing of the Community Charge in Scotland, commonly known as the poll tax, entrenched burgeoning divisions between the nations and sparked widespread social unrest.

Tensions were heightened and the power struggle transcended the corridors of power at Westminster and Holyrood.

It was also played out in the sporting arena, with the 1990 Calcutta Cup between Scotland and England at Murrayfield fuelled by the febrile political atmosphere.

The Grudge, the latest offering from BT Sport Films, is the story of the landmark Five Nations showdown, a rugby match that became so much more than a game.

Inspired by the book The Grudge: Two Nations, One Match, No Holds Barred by Tom English, the documentary is an authoritative and evocative account of the fervour of the famous match with contributions from Sir Ian McGeechan, Jeremy Guscott and Alex Salmond.

The fabled McGeechan-Jim Telfer coaching alliance invigorated Scotland after an inconsistent spell following the 1984 Grand Slam.

McGeechan, born in Leeds to a Glaswegian father, was the measured, philosophical and eloquent leader.

Ian McGeechan
Scotland and Lions legend Sir Ian McGeechan features in The Grudge

Telfer, a shepherd’s son and self-professed socialist from the Scottish borders was the perfect foil: a disciplinarian with an innate aversion to privilege. “I believe in meritocracy,” he says. “I believe in the distribution of wealth. I believe in a fair society.”

England, portrayed in Scotland as brash and arrogant, underwent a revolution of their own after winning only two away matches in the Five Nations between 1981 and 1987.

Sports psychology was embraced, a new management structure was implemented and Will Carling was made captain aged 22 as they looked towards the age of professionalism.

Sport was changing but society was transforming. Employment in manufacturing slumped in the north as deindustrialisation gathered pace. Within three years of Thatcher coming to power in 1979, 28,000 jobs had gone in Scotland and unemployment reached 15%.

By 1987, subversive undertones were replaced by overt nationalism and the Conservatives were reduced to their lowest number of seats in Scotland since the Second World War.

Thatcher appeared oblivious to the consternation and was criticised for a callousness towards the unemployed and a dismissive tone in matters relating to Scotland.

Former Scottish Secretary Malcolm Rifkind said: “She was a bossy English woman. They could probably have put up with one or even two of these but all three simultaneously was a bit too much. Her style just grated.”

The documentary masterfully intertwines sport and politics in a compelling medley of archive footage and music. The result is a universally accessible story that will emotionally engage even those who have never watched rugby.

Sport is society in microcosm and the annual international football fixture between Scotland and England in 1989 was blighted by disorder and abandoned before a ball was kicked.

Scotland rugby coach Derrick Grant fanned the flames of hostility after England ground out a victory in 1988, complaining: “England may have been the birthplace of rugby but today they killed the game stone-dead.”

The narrative around the 1990 Calcutta Cup began to build momentum after both sides won their opening two Five Nations matches.

Scotland’s meeting with France was notable for being the first time Flower of Scotland, an anti-English rebel song about the decisive Battle of Bannockburn during the Wars of Independence, was adopted as a pre-match anthem.

“There was no escaping it. Was it different to a normal Calcutta Cup? Oh, aye”
- Jim Telfer

Incidentally, calls for the sporting anthem to be replaced have grown after Telfer last week stood by his long-standing view that the song should be ditched because of its “chippiness” about the English.

Respective victories over Wales set up the tantalising prospect of a Grand Slam showdown between Scotland and England at Murrayfield amid a remarkable political climate.

Hysteria went into overdrive before the match of a generation with tickets changing hands for thousands on the black market.

The social context was inescapable and eight days before the decider, Thatcher confirmed the worst suspicions of her critics in a landmark BBC interview at the height of the poll tax protests. Her repeated and patently orchestrated use of “we in Scotland” and insistence that she was on the side of the Scottish people exacerbated the vitriol.

Nationalistic fervour gripped the streets of Edinburgh on matchday. “If you’re faced with the barrage of abuse we got, hatred is not the wrong word,” says England's Brian Moore.

“It was Bannockburn and Culloden rolled into one,” adds Telfer. “The press hyped it up. You had Margaret Thatcher and the poll tax thrown in. There was no escaping it. Was it different to a normal Calcutta Cup? Oh, aye.”

There was a lot more than rugby at stake in the landmark 1990 Calcutta Cup

The rousing rendering of Flower of Scotland, match-winning try from Tony Stranger and greatest Scottish victory of them all elevated the clash into one of the great sport stories. The context made it a defining moment in the history of modern Scotland.

Thatcher resigned months later, ending one of the most divisive premierships in post-war Britain and she still inspires strong passions of contempt in Scotland.

As Sturgeon and the SNP, now the largest party in Scotland, try to break the deadlock around a second independence referendum, The Grudge is a gripping reminder of Scottish struggle for agency and the enduring power of sport.

Sally Brown, Executive Producer of BT Sport Films, said: “The Grudge re-captures the spirit of that unique time and will prove an evocative watch both for those who watched the game in 1990, and those who are new to the story.”

Watch The Grudge on Friday 20 January at 10.15pm on BT Sport 1 or catch up on or the BT Sport app.