The Saturday interview: Asif Kapadia

Asif Kapadia sips his latte and glances at the Tour de France on the TV in Bar Italia in Soho. We've been discussing Senna, his biopic about the tragic Brazilian Formula One motor racing star. It's quietly broken box office records to become the surprise hit of the summer. Now the picture is poised for a US release that might well put it in the frame for an Oscar.

The 39-year-old Hackney-born director's film powered away from an unpromising position on the starting grid. It grossed £375,000 on its first weekend, three times more than Kevin Macdonald's 2005 documentary about two British mountaineers' near-death experience in the Andes, Touching the Void. After that impressive start, Kapadia's film looks set to become one of the most successful documentary films ever released in the UK. "At the moment, we're in third and chasing down second," laughs Kapadia. His film has accelerated past Justin Bieber's concert film, Never Say Never. It's now grossed more than £3m and is bearing down on the 2005 nature documentary March of the Penguins. "There's only one documentary we'll never overtake – Fahrenheit 9/11." Michael Moore's 2004 documentary has, like Ayrton Senna in the 1993 Brazilian grand prix, an unassailable lead in this race.

Kapadia's achievement is all the more remarkable in that his film is set in a sporting milieu often regarded as unremittingly snoozeworthy. "The challenge was to make a film that appealed to people who think Formula One is about men driving in circles in oversized cigarette packets. I guess we must have done it."

He's already thinking about the next project. "I'd love to do a film about another sport. There's a story there," he says, nodding at the telly. "The Tour de France would make a great movie. Drugs, corruption, political chicanery, guys risking their lives – everything you need for a great sports drama."

Getting permission to use old race footage was key to Kapadia's success with Senna. His is the improbable story of how an independent film-maker from east London elbowed aside some of Hollywood's biggest names to make a movie about the most charismatic motor racing star. "Lots of film-makers over the years approached the Senna family," says Kapadia. "Oliver Stone, Michael Mann and I'm pretty sure Ridley Scott all approached, and were told no. Antonio Banderas wanted to play Senna."

Why were they rebuffed? "The main thing was they all wanted to make a film about his final weekend at Imola in 1994. The family didn't want that. They preferred what we wanted to do, which was a three-act drama celebrating his life, from archive footage."

The idea for the film came in 2004 when producer James Gay-Rees read an article about Senna on the 10th anniversary of his death. Gay-Rees and Kapadia pitched the idea for a Senna documentary to British production company Working Title. "The executive said: 'You've got to meet my husband, he's Senna's biggest fan.'" That husband was Manish Pandey, who became the writer on Senna. "He's a surgeon, but he's seen every race and knows every stat. So Manish and James worked out the story and pitched it to the family. Manish was such a fan that they trusted him like nobody else."

Kapadia's CV didn't suggest he had what it took to direct a film about an adrenaline-charged sport, with a protagonist who lived fast and died young in a high-speed crash. Rather, he was known for confident, quiet, leisurely paced art films – The Warrior, a 2001 Hindi-language feature set in the deserts of feudal-era Rajasthan, and Far North, a harrowing portrait of human loneliness in the frozen Arctic wastes.

"Well, I knew a little about Formula One," retorts Kapadia. "I remember when Senna died – I was watching it with my dad and sister at my parents' house in Stoke Newington. But you're right – I was an outsider to that world, while Manish is like the guy in Dictionary Corner when it comes to Formula One, so there was a nice dynamic. And once we'd got the family's approval, that helped us get access to the archive of Bernie Ecclestone [the Formula One tycoon]. At one stage we had 15,000 hours of footage. We had to edit it down to 90 minutes – it took us four years."

But Kapadia's muted sensibility – which he learned from one of his cinematic heroes, the quietist French director Robert Bresson – paid dividends. One of the miracles he manages is to do justice to the serenity and gentleness of Senna. There's a lovely scene in which the young Ayrton, long before the Formula One duels, sits eating a TV dinner. He looks up and smiles at the camera, an image silently conveying what made him beloved in Brazil and beyond: his humility and disarming sweetness."I wanted to make a film that wouldn't just appeal to Formula One fans. That's what the great sports documentaries do – Hoop Dreams, When We Were Kings – they're human dramas first, sport second, if at all. Lots of people who enjoyed it are not like Jeremy Clarkson. Often they're women who couldn't care less about motor racing."

What captivates non-fans about Senna's character? "That he wouldn't quit, and he stood by what he believed in, and yet had utter dignity. How many sports stars can you say that of? Ali's the only other one. Ali was my hero – and my dad's – when I was a boy. And now I've made this film, Senna has become my hero, too. There aren't many real heroes, you know?"

Senna, perhaps, is not so unlike Kapadia's earlier films. "It's the story of an outsider – a Brazilian who came to Europe and took them on. A man who was slightly apart from the world he inhabited, a still centre around the noise. He reminds me of my previous protagonists." His film, too, is unafraid of dealing with Senna's faith. "My films often have a spiritual dimension which comes from my Muslim background, and I'm happy to tackle that in cinema."

Kapadia decided to have no talking heads. "I was expected to do that – cut from race footage to interviewees. Every great documentary does it. But talking heads take you out of the moment. I wanted just to make a film from the footage, not slowed down or speeded up or cluttered with chat." He also didn't want any retrospective rationalisation by interviewees, either. "These guys hated each other, whatever they say now, and I wanted to show that."

The film's central drama is the rivalry between Alain Prost and Senna, the former the Frenchman nicknamed the Professor for his coolly calculating approach to races, the latter determined to win at any cost. At the Japanese grand prix in 1990, Senna – angry and reckless – tries to overtake Prost on a chicane, but the cars collide and both crash out of the race. "You can't excuse him. He could have killed himself and Prost. I didn't want to judge him, but to understand his motivation and to show the life-or-death nature of their rivalry.

"At some points when I was editing I was thinking of them as dramatic figures rather than people. Then I stopped." Why? Kapadia says when he edited footage of Senna's mother at his funeral his responsibility to the family became clear. "I realised it's someone's life I'm dealing with, and so, morally, I felt a responsibility for the images I've never felt before. If the family had objected to the film, it would have been very tough because I'd tried to make something honest and moving." Fortunately for Kapadia, the family loved the biopic.

The last act of the film deals with the cursed weekend at the San Marino grand prix at Imola in 1994. In footage from the starting grid, Senna looks haunted. He was driving in a Williams car whose steering seemed unpredictable, was pitted against Michael Schumacher's Ferrari that he just couldn't catch, and witnessed the death of the Austrian driver Roland Ratzenberger during qualifying. "Senna generally had his helmet on, looking straight ahead and focused at the start of a race. On that last day he chose not to wear the helmet and looked in such a state – he looks in the wrong place, he looks so lonely, so unhappy, so out of love with the sport."

On that last day, Senna understeered at Tamburello corner, leaving the track at 190mph then slowing down to 135mph before hitting the wall. He died in hospital aged 34. Some think Senna had a death wish. "I don't think he wanted to die," says Kapadia. "There are people on my team who think God was saving him from himself because he's got to the position where he hates the sport so much, and the only way out is to take him out. That's certainly one reading, but I wish he'd walked away."

Maybe Senna didn't expect to die: next to him in the cockpit was a rolled-up Austrian flag the Brazilian may have wanted to wave to the crowds in honour of Ratzenberger at the end of the race.

Kapadia shouldn't have been a film director. "As a kid, I thought movies were boring. My parents would hire VHS recorders for the weekend and watch Bollywood movies. I'd get bored and go out to Stoke Newington common to play football. The movies they took me to – Grease, ET – never really appealed."

But when he was 17, then a graphic designer imagining he might become an architect, he was asked by a friend to be a production runner on a student film. "I was just carrying boxes and stuff, but being on set was so exciting. And then it was like, 'Can you hold the boom', 'Can you movie that light?' I got so entranced that I changed courses from media to film and video." He studied at Newport film school and the Royal College of Art. "I got a film education, steeped myself in Bresson, Hitchcock, all the greats."

He cites Tran Anh Hung's 1995 film Cyclo as a key influence. "It was made by a French guy living in Paris but from a Vietnamese background, and it's set in Vietnam. It inspired me to embrace my ancestry: I'm an English guy from an Asian background and I wanted to shoot in India, so I did. Plus Cyclo uses non-actors. So that inspired me to go and make The Sheep Thief in India with non-actors, which led to The Warrior."

The Warrior, his first feature, was some calling card – an epic story of spiritual redemption with minimal dialogue. Critics compared it to Welles, Ford and Kurosawa. Bafta admired the film so much it was chosen to represent the UK in the best foreign language film category at the 2003 Oscars. But the academy rejected it, arguing the film did not qualify as British since Hindi was not a language indigenous to the UK.

"They've changed the rules since. It did annoy me at the time because there I was with my first full-length film poised to win a Oscar." He went on to make a Hollywood studio thriller, The Return, starring Sarah Michelle Gellar. It's the only blot on an otherwise impeccable CV. "I learned a lot from that – this is show business, not show friendship."

As we stroll out of the cafe, Kapadia takes one last look at the Tour de France on telly. He mentions other possible film projects – a biopic of the great Indian cricketer Sachin Tendulkar or a Latin American project he declines to detail.

He says he's no longer rueful about not winning that Oscar. Senna, which has already won the 2011 world cinema documentary audience award at Sundance film festival, may do what The Warrior could not. "Exit Through the Gift Shop, the Banksy film, won that award at Sundance, and got an Oscar nomination, so I'm hopeful Senna could follow suit. But one thing you learn from sport is you'd be mad to count on winning."