The Tunnock’s chocolate factory rises above Uddingston, a small town seven miles south-east of Glasgow, with the authority of a cathedral – a cathedral of snacks – the giant Caramel Wafer on its front glowing red and gold in the cold Lanarkshire night.

This place, in truth rather kitschy, lacks the haunted solemnity of Culloden moor, and the date 14 January 2016 – unlike Bannockburn 1314 – is not etched on the undaunted heart of every Scottish school child and sports fan. But it was here and then that an unlikely battle in the war for Scotland’s soul was fought. A group calling itself the Scottish Resistance – the so-called “shock troops” of Scottish nationalism – staged a protest against the decision by the company to rebrand its best known product as “the great British teacake” in adverts on the London underground. This marketing decision made Tunnock’s, in the eyes of the Resistance, “a bunch of traitors and collaborators”, so they turned up outside the factory with a microphone, an amplifier and a home-made sign featuring the Scottish lion rampant, which they claimed had been removed from packaging.

“We are the Scottish Resistance!” shouted the group’s 60-year-old founder, James Scott. This cri de coeur did not impress a small group of hecklers, among them Rita Calder, a 68-year-old from nearby Blantyre, who staged a counter-protest by stuffing a teacake into her mouth, chewing it slowly and with great pleasure in front of the Resistance. “That lot are a shower and an embarrassment to Scotland,” she says later. A committed unionist, she had been upset when the large saltire hanging on the front of her garage was defaced with graffiti including “Death to the Union” and “We love you, Nicola”. The flag, she feels, belongs to everyone in Scotland, and has been “hijacked” by the independence cause. “So my humph was up,” and she decided to take out that anger on the nationalist group making all the headlines. “I’m not a confrontational person,” she says, “but he attack on Tunnock’s was one step too far.”

‘My humph was up. The attack on Tunnock’s was one step too far’ … Rita Calder counter-protesting against the Scottish Resistance. Photograph: Hemedia

The deeds of that day were not recorded on parchment or vellum, but rather Buzzfeed and Twitter, and it was the moment when the Scottish Resistance became known beyond Scotland. Now, in the week the country would have become independent had the referendum been won by the nationalist side, it is a good moment to get to know these protesters who, in the face of scorn and mockery, refuse to give up the fight. Numpties, zoomers, eejits – these are the names that bounce off their thick skins. Those sympathetic to their cause and tactics call them patriots. Others view them with amusement. Their actions have a tendency to turn into comedies of errors. A recent ritual public burning of a David Cameron speech was delayed when the lighter went missing. A few years ago, a leading member of the group attempted to occupy a bank in Glasgow, only to find that the branch had closed. Little wonder that in Deccember JK Rowling tweeted “The Scottish Resistance are comedy geniuses”, and claimed to be buying their T-shirts as joke presents for union-supporting journalists.

“They are laughing at us, but it doesn’t bother us,” says Sean Clerkin, 54, a prominent Resistance member. “They know how serious we are. They’re afraid of us.”

Wait – Rowling is scared of the Scottish Resistance? “Yes, absolutely … Afraid of groups like us getting Scottish independence and redistributing income from rich to poor, so that JK Rowling is no longer the rich woman that she currently is … The millions that she’s got in her bank account should be redistributed to the poor, to the working class. She’s afraid of what we stand for.”

So who are the Scottish Resistance and what do they stand for? James Scott formed the pro-independence, anti-austerity group in January 2014. He claims they have 7,500 members, but this figure is based on Facebook likes; there are 100 or so card-carrying members, and only a handful who turn up to events. Nevertheless, their profile and impact is out of all proportion to their numbers. They have a knack for stunts that make the papers, such as their attempt, in December, to have Cameron arrested for war crimes.

Meanwhile, the Scottish Conservative leader, Ruth Davidson, credits Clerkin with changing the course of history. During the run-up to the 2011 Holyrood election, Clerkin and other protesters pursued the then Scottish Labour leader Iain Gray into a Glasgow sandwich shop; Gray’s perceived reluctance to discuss Labour’s policies, Davidson argued, proved so damaging to his public image that it allowed the SNP to form a majority government, leading in turn to the independence referendum and all the political turbulence that has followed. The public, she said, “saw Iain Gray run into a Subway and thought he was a diddy and said: ‘That man shouldnae be first minister.’”

Known for his forceful heckling of politicians, Clerkin insists that he does not get a buzz out of confrontation. Political leaders have grown too used to living in protective bubbles, he says, and it’s his mission to prick them.

It will be surprising if the Resistance do not make its presence felt during the present Scottish election campaign. Even Nicola Sturgeon, a saint in the eyes of many SNP supporters, is considered a sinner by those most zealous nationalists frustrated that she isn’t calling a second referendum quickly enough. “I don’t believe she wants an independent Scotland,” Clerkin says. “I think she’s just in it for the power.”

What about Clerkin’s own motivations? It is often suggested that he is simply an attention-seeker and narcissist. In Edinburgh earlier this month, around 100 independence supporters gathered outside the Court of Session in support of IndyCamp, a bivouac of caravans and tents assembled next to the Scottish Parliament, which the authorities were trying to have removed. The atmosphere was upbeat, but some IndyCampers, noticing Clerkin and Scott, turned hostile. “Don’t you know you’re undermining the cause?” shouted a woman with red hair. A young, bearded man snarled at Clerkin: “It’s all about Sean, isn’t it?”

That’s a question worth asking. So, is it? “I reject that completely,” says Clerkin. “I’ve never been interested in attention-seeking, or money, or going up the grubby pole.”

When yelling through his megaphone, Clerkin can sound like a Glaswegian Dalek. He has been accused of being a fanatic with nothing in his life but protest. Not so, he insists. He lives with his elderly parents in a bungalow in Barrhead, helps to look after them, and works in a call centre. He is father to an 18-year-old daughter. He sings the songs of Bob Dylan in the shower. “I have a girlfriend as well. I’m not a robot. I’m a human being.”

The Indycamp protest outside the Scottish Parliament in Edinburgh, some of whom believe the Scottish Resistance are ‘undermining the cause’ for independence. Photograph: Murdo Macleod/The Guardian

How seriously should we take the Scottish Resistance? They have a public profile somewhere between two Monty Python sketches – the Spanish Inquisition (“Nobody expects … ”) and the People’s Front of Judea. Yet, while many will disapprove of their tactics, it might also be true to say that they do reflect a not insignificant sector of Scottish society who feel frustrated, thwarted, bewildered, paranoid and even scared following the no vote. Arguably, they reflect the emotions, most of all, of the so-called “missing million” – those people from poor communities who had never voted before the referendum, and who are now scunnered in the extreme that their X for independence didn’t count for much.

This all exists amid a broader context of widespread and growing disenchantment with UK institutions. The recent Scottish Social Attitudes survey shows that less than a quarter of Scots believe the Westminster government acts in their best interests. Less than half feel the BBC represents Scotland adequately.

“All that indy ref emotion had to go somewhere,” says Peter Geoghegan, author of The People’s Referendum: Why Scotland Will Never Be the Same Again. “Traditionally, politics has changed very slowly here, but we went through this incredibly intense political moment and we’re not out the other side yet. It can be difficult for people to find a mooring in that. Anger, alienation, rejection and fear is what you can end up with. So to just see the Scottish Resistance as comical and silly misses the sociological significance, and doesn’t take account of where this has come from.”

On a cold, wet Sunday last month, the Scottish Resistance came together within the portico of Glasgow’s Gallery of Modern Art to remember one of their fallen. There were 20 or so people gathered, but one face was missing. Philip Malloy had taken his own life, at the age of 27, a year before. Resistance members and relations held blown-up photos. In one, taken at a rally in George Square, Malloy was dressed as a Roman legionary, with a saltire slung over a shoulder. “Phil was my right-hand man in the Scottish Resistance,” said Scott. “I tell you something, I’ve never met a more patriotic Scot … One Phil Malloy is worth two million bloody unionists.”

Scottish Resistance members gathering in Glasgow to remember their friend Phil Malloy, who took his own life last year

Music played through a small amp: songs from Les Misérables; Andy Stewart’s A Scottish Soldier. Someone lifted a can of Buckfast heavenwards. A neon artwork glowed above their heads, bright slogans of ironic patriotism displayed above the doors of the gallery: We ♥ Bonnie Prince Charlie; We ♥ Alcohol; We ♥ Failure. Phil Malloy’s father, also Philip, a solid-looking man with silver hair, remembered his boy: “He grew up with me telling him all about Scottish history. I told him about the Highland Clearances and all the bad times, the tyranny we went through for hundreds of years by the English … He’d say: ‘Da, why are we no’ independent?’” Malloy said that those who had voted no at the referendum were cowards. “I know my son wasnae one. James called him a Scottish foot-soldier. Well, to me he was a general, and I loved him very much.”

Afterwards, over a drink, Malloy explained that his son had got himself into trouble before becoming enthused about Scottish nationalism. He had a history of prison, once for assault. Joining the Resistance marked a positive change.He found a sense of purpose and loved speaking at rallies. “It meant an awful lot to him,” he said. “He told me what they were trying to achieve, and it was the first time I had seen a determination in him.”

But life began to get on top of him. He lost his job as a barman, had his benefits sanctioned, and became homeless – all this on top of the no vote in the referendum, which he took hard. It was, his father says, one of the things that led him into darkness. He was in the Clyde for five weeks before police divers found him.

On 24 March 2016 – the day Scotland would have become independent had the vote gone the other way – Scott awoke at home in Rutherglen to the knowledge that his country was not yet free, but determined to play his part in freeing it before long. The Scottish Resistance have been campaigning for a second referendum to be held in 2017 although Scott, personally, favours some sort of unilateral declaration of independence.

“To me it’s just another day,” he says, over coffee. “They were never going to allow Scotland to get independence.” He believes the referendum was rigged, and not only that, but fixed so that 45% of the electorate appeared to vote yes in order to associate the movement with the doomed Jacobite rebellion of 1745. “That number’s in the fuckin’ Scottish psyche,” he says. Such conspiracy theories are not uncommon in the outer reaches of the independence movement; belief that the referendum was “stolen” is widespread and perhaps, in its way, consoling.

The founder of the Scottish Resistance works as a self-employed financial consultant. In protest against their previous opposition to independence, he boycotts Tunnock’s, B&Q and Asda, and would boycott the BBC, too, if he had his way. “The wife sticks it on for EastEnders, but I keep turning it over.” His activism has required personal sacrifice. “There is a wee bit of a rift between me and my daughter. She’s a police officer and she wants me to stop protesting.”

He joined the SNP in 1973 and was a member until last year, having been suspended for his part in protesting at a Labour rally in Glasgow during the general election. The Scottish Resistance is regarded negatively by the leadership of the SNP. “If you want to win a referendum, you can’t afford to put any people off unnecessarily,” says one senior party insider. “The polls indicate that a huge number of people who voted no would potentially vote yes in a future referendum. If there’s an element among independence supporters who are putting across an unattractive image, then that raises a wholly unnecessary barrier.

“Even the name is unappealing. Who are they resisting? Surely not the 55% who voted no, because they are the people we need to try really hard to persuade to vote yes next time.”

SNP documents from the early 1980s, from whence sprang today’s Scottish Resistance. Photograph: Peter Ross

The name has history and resonance. It calls to mind the Wars of Independence, when Wallace and Bruce wrote their names in English blood. More recently, Scottish Resistance was a phrase associated with a particular school of thought that developed within the SNP, in the early 1980s, that future success would be built upon working-class support. In a 1982 pamphlet, Alex Salmond – then still a young firebrand – quoted with approval a motion passed by the SNP party conference “that a real Scottish resistance and defence of jobs demands direct action up to and including political strikes and civil disobedience on a mass scale”. In a letter to the Glasgow Herald that same year, he reiterated the point: “Given the impotence of their present political representatives, working people are starting to mount their own ‘Scottish Resistance’.”Scott, no doubt, knows all this. He is a keen student of history. A much less well-known aspect of Scottish Resistance activity is the guided walks they offer to places of historical interest. The idea is that the Scots need to be “re-educated” about their own history so they no longer regard it from a pro-union perspective.

He finishes his coffee and leads the way across the street to Rutherglen’s Old Parish Church, where, in 1305, William Wallace was betrayed to English forces. “I got married here in 1979,” says Scott. “On the Wednesday, there was a rehearsal. I went into the church and there were all these union flags. So I says to the minister, ‘See when I come in here on Saturday, I want all these removed.’ I did not want to get married in a church, associated with Wallace, where they were flying that flag.”

He glares up at the red, white and blue flying from the town hall. For years he has been trying to persuade the council to raise a saltire instead. He won’t give up, though, on the flag, or anything. His seriousness of purpose insulates him against mockery. Look at David Icke, he says – people used to laugh at him. “We will just keep protesting until things happen. No one ever thought the Berlin Wall would come down.”

What happens, though, if Scotland does, eventually, become independent? What will Scott and the Scottish Resistance do with their lives then?

“Well,” he says, “there’s Tibet … ”