THE thing I want to know, I say to the screen writer, is when your director is also your partner do you ever argue on set about whose turn it is to put the rubbish out when you go home?

Sitting in his Edinburgh home Paul Laverty laughs at the very notion. “The film-making part is the easy part, as you can probably imagine,” he concedes. “Work is much easier than life.”

Given that Laverty and his partner, director Iciar Bollain, have three children and have now made three films together, too, it’s probably fair to say that the pair of them are managing both sides of the work-life divide well enough.

Now in his early sixties, Laverty is one of Scotland’s busiest screen writers. And one of the its most adventurous. Since he wrote his first script, Carla’s Song, for the director Ken Loach in 1996, he has written 16 films and counting, including Loach’s Sweet Sixteen, Looking for Eric and I, Daniel Blake. It’s been a formidable creative partnership.

But then so is the one he has with Bollain. Their latest film Yuli received its UK premiere at the Glasgow Film Festival in February and is now about to go on general release. A biography of the Cuban dancer Carlos Acosta, it stars Acosta himself and mixes up both naturalistic drama and choreographed recreations of that life story (at one point Acosta even dances the role of his father).

It is an ambitious approach that works, partly because the dramatic performances are so good, partly because it’s never a chore to watch Acosta and his young company dance and partly because Havana just looks like a city built to be filmed.

The idea for the movie, Laverty says, actually came from former BBC Scotland head of drama Andrea Calderwood who suggested he have a look at Acosta’s biography.

“I was always wary of doing a biopic because first of all, I’ve never done it before, and secondly it’s always safer somehow if the characters are invented or long dead.”

Still, he agreed to meet Acosta and they got on well. “He was an intriguing man. In fact, he reminded me of my old mates in Glasgow to be honest. He was full of mischief. He didn’t play the superstar. He was humble, but you could see he had a great presence and a fascinating life story.”

Eventually, Laverty and Bollain travelled out to Havana to watch Acosta rehearse with his young dance company, which prompted a lightbulb moment. “I saw someone holding a cigarette in one hand and then holding her shin to her forehead with the other and I was absolutely gobsmacked by the casual athleticism of it all.

“And then we watched them dance. And that’s when we thought, ‘Well, this is a big jump, but let’s dance some of his life.’ It just made sense.”

The dance sequences are an example of Laverty’s creative flexibility (Bollain’s too, for that matter), but in many ways Yuli is typically Lavertyesque in its adroit folding of the political into the personal.

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The film is about Cuba – “there’s something sensuous about the place,” Laverty suggests - masculinity and discipline and family. In a way, he has noted before, it’s an anti-Billy Elliot story. It was Acosta’s father, not Acosta, who wanted his son to dance. In biopics, he says, you don’t want interesting event after interesting event. “You’re hungry for relationships.”

The question then arises of his own. What was Laverty’s relationship with his own father? It’s a glib segue that he does the courtesy of taking seriously.

“Although it’s about someone else’s life you have to find things you are able to write about with some conviction and sensibility. So, you do examine your own life,” he admits.

“Father-son relationships are always massively complicated, and I suppose I was very lucky with my father. He was a complicated and flawed character like we all are, but he was a very loving and imaginative man. We loved each other deeply despite all the contradictions.”

That said, he was sent away to seminary when he was 11 and he drew on that when it came to Acosta’s own troubled relationship with his dance school.

When you leave home so young, Laverty suggests, there’s an inevitable sense of isolation and loneliness. That was something he could tap into writing Yuli.

“It’s in a totally different place and a different country and a different time. But certainly, that feeling of a child going away from home is something that marks you forever, I think.”

If you were making a biopic of Laverty’s own life you could do worse than start the story with the 11-year-old boy leaving home to go to seminary.

“It’s a very strange institution. For me, I was lucky because I loved sports and I was quite sociable, and I made great friends so generally speaking it was a very positive experience. But for many of my friends it was very tough. For people who are more sensitive I think it was a very painful experience.

“I would never send my own sons, but my parents did it for the best of reasons and I think they were just different times.”

Born in Kolkata, Laverty has been something of a traveller all his life. He lived in LA and Madrid before settling in Edinburgh. But he was raised in Wigtown, and at 11 he was sent to Langbank, then spent four years at Blairs College in Aberdeen and two more years at the Pontifical Gregorian University in Rome.

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When he left that world, he studied law in Glasgow. And then in his twenties decided to go to Nicaragua, a country at the time in the midst ofa US-backed Contra war against the Sandinista revolutionary government. The question why seems relevant, Paul.

“I think in your mid-twenties you’re bursting with curiosity. I think because I felt so very claustrophobic for so long it gave me a never-ending appetite and curiosity for the world. That’s still insatiable. I still have that in my gut,” he says. “I wonder if seminary has got something to do with it.”

Fair enough, but Nicaragua? “Like many people in their twenties you become interested in politics and of course the Sandinista revolution was remarkable. For our generation it was the Spanish Civil War, I suppose. You have a tiny population of only three million who taught its population to read and write, wiped out polio, had a successful popular revolution and the United States was determined to crush it, using terror as a main tactic.”

When he got there, Laverty went to work for a human rights organisation, taking statements from those who had been attacked by the Contras. And sometimes he talked to the other side too. “I spoke to people who were trained by the CIA and told to finish people off.

“It was a very complex story and a real lesson in real politick and what I saw and witnessed was the complexity of systematic violence. Having interviewed people you learnt what terror was like on the ground. When you’re young to see such cruelty is a lesson that you never forget.”

It’s hard to believe you could emerge from that experience – from seeing what Noam Chomsky called “the manufacture of consent” through speeches and propaganda and embargoes and violence – and not be politicised. Over the years Laverty has addressed the Spanish Civil War, workers’ rights, the inhumanity of Britain’s welfare system in his scripts.

This is the lens though which he sees the world. During our conversation he talks about President Trump’s approach to Cuba (in short; not a fan) and regrets the current state of the country he visited in his twenties. “It gives me great pain to see how that Sandinista revolution has been betrayed by Daniel Ortega.”

What I’m wondering, I tell him, though is how the young man who returned from Nicaragua decided that cinema of all things was the vehicle to talk about all of this.

“I was writing articles and reports and after a while it could drive you mad. I thought it would be a challenge to see if I could do something more creative. In my naivety I decided to make a film.

“I prepared a treatment and sent it absolutely everywhere. Most people ignored it, of course. Who was going to go and do a film in a war zone with a writer who had never written a script before?”

The answer turned out to be Ken Loach. “Ken contacted me and was very curious, something he has had all his life. He was curious and open, and he wasn’t interested in CVs. He was interested in what I had seen and what I had done and what I had heard.

“When I met Ken, he said, ‘Never mind all this treatment, see if you can write a scene.’ That was a total liberation because it was about giving life and shape to a fictional character, giving them dialogue. And it was just like a drug. The first half of Carla’s Song just popped out.”

It was the beginning of a long and fruitful working relationship. A friendship too. “He’s a remarkable man,” Laverty says of Loach. “He’s got a real fire in his head, a real fire in his heart, great curiosity, great energy and he comes alive when he works. It’s been a total stroke of luck to have linked up with Ken.”

Loach could say the same of him of course.

Yuli is released on April 12 following a Live Film Event at the Royal Opera House on Wednesday with a Q&A from Acosta and the filmmakers, live streamed to cinemas nationwide (tickets available at acostafilm.com)

CAREER HIGH

Getting the first commission for Carla’s Song was a real dose of adrenalin after being on Enterprise Allowance for so long. I’m always grateful for that. It opened up the possibility of getting paid for your work.

CAREER LOW

When you work very hard on a project and then you make miscalculations. There’s one in particular. I don’t want to mention anybody’s name. It wasn’t their fault. it was a misjudgement on my part. And when people oppose you sometimes it can bring out the worst in you and you become even more stubborn. I continued with a project I should probably have rethought.

But you learn from your mistakes and I think failure is greatly underestimated. The problem with film is so many people might have a failure, but they don’t get a chance to recover from it.

BEST ADVICE RECEIVED

"Whatever you can do, or dream you can do, begin it. Boldness has genius, power, and magic in it. Begin it now." - Goethe. I once visited his home in Germany too, a nice room to write in.

FAVOURITE FILM

The opening scene of Modern Times with Charlie Chaplin still takes my breath away because of its comedy and the ideas underneath it.

IDEAL PARTY GUESTS

The 16th-century Dominican priest Antonio Montesinos. He haunted my imagination for years before making the film Even the Rain. So, I am bursting to see what he was really like. And I want him to tell me who killed him.

Can I invite Nina Simone? Sadly departed, too. Her voice would melt us all at the dinner party, even just speaking, and I would ask her to tell the story about how she got the money from her dodgy agent by taking a gun from her handbag.

I would love to invite two writers, too. Primo Levi, whose courage and insight still leave an impact from reading him as a young man, and Indian writer Arundhati Roy; there is a twinkle in her eye, she is fiercely intelligent, and I bet she has great sense of humour.