AN olive field in Spain. Two Scotsmen, George Watters and Jock Gilmour, have taken up position on the high ground facing the enemy. They’re outnumbered but they push forward. The battle intensifies and Jock is injured. “Leave the stretchers for the men who are worse than me,” he tells George. But he doesn’t realise how badly he’s been hurt. “He was pumping out blood,” said George when he remembered the death of his friend. “Even the olives were bleeding that day.”

A large room in the Gorbals. Two young theatre producers, Robbie Gordon and Jack Nurse, are telling me why they’ve written a play that recreates that bloody day in Spain. In front of us is a bare stage filled with some bar stools and tables, which in the play becomes the frontline of the Battle of Jarama, one of the bloodiest confrontations of the Spanish Civil War. The bar stools become barricades, the tables become the banks of the Jarama River, and the wooden floor becomes the field in which Jock bled to death.

Sitting in front of the stage, Robbie explains why he and Jack wanted to turn the story of the battle and the war into a play. Robbie, who’s 25, admits he wasn’t actually hugely familiar with the Spanish Civil War at first or the part that Scots volunteers played in it, but then one afternoon his grandfather told him about four of his friends from Prestonpans: George Watters, Jock Gilmour and two others, Bill Dickson and Jimmy Kempton. All four fought in the war and Robbie became engrossed in their stories. He also started the see parallels between the experiences of the four men and what’s happening in politics today. “There are echoes of them everywhere,” he says.

So, what do we know about the four men? We know they were all miners and we know they were all politically engaged and inspired by left-wing politics, with George Watters being one of the most passionate. In 1936 the British Union of Fascists held a rally at the Usher Hall in Edinburgh and George decided to disrupt it. Right in the middle of the meeting he stood up and sang the left-wing anthem the Internationale, which started an all-out fist fight. George was arrested and fined, but he’d made his point.

Robbie says he feels a particular connection with George because he can trace some of the passion and politics in his own genealogy. Like George, he grew up in Prestonpans; his grandfather was also a bricklayer who went into radical politics, becoming a trade unionist and Labour councillor. Robbie also identifies with the reasons George went out to fight in Spain.

“George saw the Popular front party, the party that had just been elected in Spain, as something to aspire to,” says Robbie. “They had managed to elect a government that had put in place a guaranteed minimum wage, the enfranchisement of women, reduction in military size and influence, compulsory education for young people, eight hours a day - amazing, radical, left-wing policies at the time, and even now, and I think working class people all across the UK said ‘this I what we want’. Then they saw the fascists trying to topple that.”

Robbie’s colleague Jack, who directs the play, was similarly impressed with how engaged many working men and women were in politics in the 1930s. “In a world without online news or mass media, they were extremely well read and had a knowledge of what was going on in the world,” says Jack. “There were bookstores all over Glasgow where you could read up on everything despite the fact that they were working endless hours.”

The play is not a work of glorification though and does reflect some of the subtleties– one of the four men Jimmy Kempton, for example, wasn’t motivated purely by politics – in fact, he was skint and needed the cash he would be paid as a member of the International Brigades. “Jimmy had no money,” says a character in the play at one point, “And Spain was the latest opportunity to keep his family fed.”

However, Daniel Gray, an expert on the Scottish contribution to the Spanish civil war and an advisor on the play, says the overwhelming reason for Scots going to fight was the political cause.

“The cause was to fight fascism,” says Daniel. “It brought together the hunger marches and all sorts of progressive causes and in Spain they saw not only the chance to fight fascism but also to stop a second world war and an invasion of Britain. The republican government in Spain was a left-leaning government and they thought ‘if we can keep that going there, we can export the revolution back to Scotland’.

“Of course, there would have been rogues and different characters but don’t forget they would have been vetted by the Communist party. At the start, you could just drift over to Spain, but after Christmas 1936 you would be vetted to check that you were going for the right reasons. About 70 per cent of the men who went were in the Communist party.”

Everyone involved in 549 – Jack, Robbie and Daniel – say they’ve felt inspired by the motivation and passion of the Scottish volunteers. Daniel says he started out on the project with a challenge: imagine what it would be like going to another country’s war illegally. You’ve probably never left Scotland, you probably don’t have a passport and yet you go. “I started out in admiration and that’s how I feel still,” says Daniel. “They were probably the most forward-looking generation that’s ever existed.”

However, Daniel and the others say they were also aware of the risk of glorifying or romanticising war. The Spanish conflict has taken on a certain kind of romance because of the poetry and literature it inspired, but this was a battleground with the methods of the first world war and the tactics of the second; it was brutal and horrendous and anything but romantic. The producers of 549 (the title was inspired by the number of Scots who volunteered) were also keen to learn the lessons. What does the Scottish contribution to the Spanish Civil War mean for the modern world? What can be learned about radicalism, fascism and the fight for equality and fairness?

The first lesson, as far as Daniel is concerned, is that, 80 years on from the war, we still have to be wary about the risk of fascism. “The word that the members of the International Brigades always used was vigilance,” says Daniel. “The danger changes, it changes face and it calls itself by a different name, but vigilance is the key word and plays like 549 – all sorts of art – play an important role in keeping us awake.”

But here’s another interesting question for young men like Jack and Robbie: does the kind of radicalism that’s needed to take on fascism still exist? I suppose the real question for them is: could you ever imagine yourself doing now what George and Jock did in the 1930s: volunteering to fight in a foreign war?

Jack says it’s hard to put himself in that position because of everything that’s changed in the last 80 years. “We are one of the first generations that may not know anyone who fought in the Second World War,” he says. “We’re close to losing that direct link. There’s a bit of distance and we maybe forget.”

However, both Jack and Robbie believe radicalism is still alive in young people, albeit in different ways (and not all of them positive). On the table in front of us are the scripts and bits of lunch and, of course, our mobile phones and Jack says he sometimes worries about some of the consequences of phones and the internet for his generation – do young people feel “radical” just because they have tweeted their outrage or liked a post on Instagram?

“It seems like the internet as a theory can be a real force for good,” says Jack, who’s 24. “But we haven’t quite worked out how to use that yet. On paper, it’s fantastic - it’s a wealth of knowledge that anyone can access and it’s unlimited – but somehow it’s not working.” At the same time, though, Jack believes we’re facing a critical time in politics in much the same way we did in the 1930s. “There’s a crucial parallel with our times,” he says, “with the great depression in the 1930s and the financial crisis in the 2000s and in both times we’ve had the rise of the far right. What we’re looking at is how do we approach tackling that and combating it.”

Robbie says that, in some ways, it’s happening already. “I think the Conservative government is threatened by the electability of parties that have really left-wing policies,” he says. “We’ve also got such a broad spectrum of causes because of the internet and social media and we’ve just had this amazing movement of Extinction Rebellion which seemed to come out of nowhere. We’re at a point where party politics is just the surface. Radicalism is still alive.”

Is there a darker side to it all though? Robbie is certainly aware that there’s a potentially more troubling parallel at work with the Spanish Civil War. In the 1930s, a group of young men inspired by radical politics went off to fight in a foreign war; 80 years later, different young men have been “radicalised” to go off and fight for the Islamic State. Robbie says he sees it as the same action for an entirely different cause, but Daniel Gray rejects the comparison. “I have trouble with any parallels at all,” he says. “We’re talking about such different circumstances and different times. I think modern times are an awful lot more complicated.”

Progressive radicalism is still burning though, says Robbie - not least in George Watters’ children and grandchildren – “they are still very left wing and liberal and empathic and still combating fascism in their own way,” he says. Robbie is also intensely proud of being able to tell the story of George and his comrades and their roles in the war.

As for what became of the four men, their fates were mixed. Jock Gilmour was killed at the battle of Jarama in February 1937 and Bill Dickson, the youngest of the four, died a few months later at the battle of Brunete. Jimmy Kempton on the other hand decided he wanted to leave the International Brigade but was imprisoned by his own side before eventually travelling back to Scotland.

George Watters was imprisoned too, but by Franco’s side and spent time as a POW. His wife Ellen believed him to be dead though and only discovered he was alive in the most extraordinary way. She was sitting in the cinema watching a newsreel of British soldiers being repatriated from Spain and, suddenly, there in the middle of the crowd, she spotted a familiar face – it was her husband, alive after all; it was George.

George himself continued to believe in the cause he fought for in Spain and, in the play, he explains his motivation. “Fascism is a disease we must kill,” he says. “All the things we’ve achieved in life are through conflict and strikes. There will never be a day when ordinary people say ‘I won’t have to fight again’.”

549 is at the Traverse Theatre, Edinburgh on June 6-8, St Luke's, Trongate, Glasgow on June 11 and Platform, Easterhouse, Glasgow, on June 12. Thereafter, it is on tour around Scotland.