Bob Marley: So much things to say...

When Oscar-winning Scottish director Kevin Macdonald was at boarding school in the Highlands of Perthshire in the early 1980s, he had a passing interest in the music of Jamaican reggae legend Bob Marley and his band, The Wailers. "I do remember that one of the first half dozen albums I ever bought was Uprising," he recalls of Marley's 1980 album. "I remember when Bob died. I remember that news. I would have been 13 (in 1981)."

Macdonald (whose new film, Marley, is released this week) also listened to music from former Wailer Peter Tosh and other reggae artists. "I wasn't an obsessive fan, but when you listen to Uprising, you're sucked in by the melodies, which are so pretty and catchy. It is accessible, but then there is the political and radical element to it. And then there's all that other mystical side."

The youthful Macdonald had no idea who Haile Selassie (the Emperor of Ethiopia) was or why he mattered so much to Marley. Nor did he envisage that he would one day make a film about Bob Marley. He was just one of the huge number of white teenagers who responded to the mixture of rebelliousness and optimism that characterised Marley's music. What he hadn't then realised was the "political, religious and philosophical" message that Marley's songs carried for Third World fans.

"The way to understand Bob is as the first Third World superstar," the director says. "He is the only giant, not just of music but of the arts in general, who is recognised around the world, but who comes from the Third World. The fact that he grew up in a one-room hut and slept on a dirt floor is key to who he is and what his appeal is."

On the day I interview him, Macdonald is about to set off to Bath for a special screening of his film at the Little Theatre Cinema – and to discuss Marley's life and career with the poet Benjamin Zephaniah. This was the cinema that Haile Selassie himself used to visit when he spent the war years in Bath.

It's easy for rationalists to be sceptical about the claims of god-like powers made on behalf of Haile Selassie, the diminutive Ethiopian leader revered as a messiah by Rastafarians. However, Macdonald argues, the cult around him isn't as outlandish as it may appear.

"I think it's fascinating. I see Rasta as being a product of the search for identity in the ancestors of slaves... people in Jamaica in the mid-20th century were taught at school about British Kings and the American War of Independence. They weren't taught about African history. It (Rastafarianism) is a way of saying, 'we don't want to be second-class citizens of Britain or Europe. We want our own identity'. Reaching to Ethiopia is about saying that there's a royal family of our own, and they've got a lineage far longer than anything in Europe."

Macdonald wasn't first choice to make Marley. When American businessman Steve Bing negotiated the music rights for a Marley film, the original idea was that Martin Scorsese would make the movie. Bing's Shangri-La Entertainment had produced and financed Scorsese's Rolling Stones doc, Shine a Light. However, it became apparent that Scorsese's multiple other commitments wouldn't leave him enough time to complete the project. Enter Silence of the Lambs director, Jonathan Demme, who started researching and shooting the Marley film before stepping aside for reasons which are still unclear.

Bing's window of opportunity to make the film was limited. "He had bought the rights for five years or something," Macdonald recalls. With the clock running down and determined to get the film made, he hired Macdonald.

Marley's family had been suspicious of previous attempts to make Marley films. In particular, they'd resisted biopics on the grounds that it would have been well-nigh impossible to cast the central role. However, by the time Macdonald went to speak to Ziggy Marley (Marley's oldest son "and point person for the family"), it was clear that the family were keen for a documentary to be made. "They felt that the people who were talking about Bob and claiming to know about him were representing a Bob they didn't necessarily think was correct. I came to them and said I wanted to make a film about the person." The film would be his quest to discover Marley.

The reggae musician's children, especially the younger ones, didn't know their father at all well. They hadn't lived with him. Even when Marley was on his death bed in 1981, they couldn't get close. There were so many other hangers-on. "They've all said, when they've seen the film, that they've learned a lot about their father. That was a big part of the impulse (in agreeing to the film) for them."

Marley's legacy remains a matter of fierce and often bitter debate. What the documentary makes very clear is that neither Bunny Wailer, nor the late Peter Tosh (the other two original Wailers) were at all happy about the influence that Island Records boss Chris Blackwell exercised on the band.

"Bunny Wailer hates Chris Blackwell," Macdonald notes. "He feels like he took Bob away from Jamaica, that he broke the Wailers up. I don't think it's really true, but from Bunny's perspective it is. Also, there is this residual resentment of the white man who has profited to an unseemly degree (as he would see it) from the labour of the black man."

Macdonald is friendly with both Bunny Wailer and Blackwell. He elicits revealing, affectionate and humorous interviews from both of them. They may have disliked each other, but they both warmed to the film-maker and trusted him to represent their views fairly.

Speaking to Macdonald, it becomes apparent that he has a fervent admiration for Marley. His film underlines Marley's relentless work ethic and his determination to become an internationally successful recording star. He didn't hide his ambition to reach the broadest audience possible. He was neither doting father nor faithful husband. However, Macdonald insists that Marley retained his idealism. He gave away much of his fortune and kept his ties with his old friends in Trenchtown. The ganja smoking was more to do with religious beliefs than with hedonistic self-gratification.

"The thing with Bob is that he never lived high on the hog. He always lived in a single bed. He always lived in a commune, effectively, with his band. He never lived with his children or his wife. Rasta was the most important thing in his life."

That ferocious drive to succeed was partially (Macdonald speculates) a reaction to his background as a mixed-race kid rejected by his father. Marley was the son of Norval Marley, a white Jamaican with a very chequered background and more than a hint of Walter Mitty about him. "I got obsessed with him [Norval] and spent way too much time trying to find out about him. The less you find out, the more obsessed you become."

Making a film about Marley is an exercise in detective work as much as of storytelling. Archive material is skimpy and there are fewer photographs than you'd imagine. There are also many family members and contemporaries who have their own partisan view of Marley.

Macdonald reacted to the challenges that have defeated so many other would-be chroniclers of the legendary reggae star by trying to be as straightforward as possible. "I thought, 'I am going to make a very, very simple film'. I guess it's the most conventional film I've ever made in terms of style. It's about Bob and it's about people talking. It's oral history, I suppose. That was the concept: to let the complicated story be presented in the simplest way."

'Marley' is released on Friday