People can't get enough of 'Senna'.

20 years after his death, the Brazilian racing driver is still heralded as one of the great legends of his sport, with his charisma captured in Asif Kapadia's biopic, screened again this evening on ITV.

Here's Asif's interview with HuffPostUK from a couple of years ago, when his film first came out, and found an audience that stretched far beyond the traditional Grand Prix fanbase. What was it about this shy young man that captured the imagination?

"Because he was a genius, at the height of his profession, but somehow managed to remain an outsider from the establishment of it all," says Kapadia.

"And he was very serious about his sport, a tough guy on the track, intensely competitive. But outside of the car, he worried for all his competitors, he was incredibly compassionate and gentle with the people around him. And, of course, he had movie-star looks too, and could speak so elegantly and eloquently. So he just had it all."

It must have been very strange for the director to share so much time with someone he had never really focused on before, something Kapadia confirms wholeheartedly:

"Absolutely, I’ve spent so much time intensely studying Senna’s life and the people around him, and who he was - literally hours and hours of footage. It takes over your life, I've even dreamed about him. I've never met the man face to face but I feel I know him now, and how thinks. It's very strange."

But what has meant the most to Kapadia has been the reaction to the film of the Brazilian icon’s family and friends:

"It was very emotional and very difficult for them to watch, because there was lots of material they hadn’t seen before," he remembers. "But they were happy that the film is the measure of the man they knew. They said I had brought out the whole person, which was gratifying. There were lots of tears while they watched. It was obvious he stays very close to them.

"I was also touched that Ron Dennis (Senna's old team manager) said it was an accurate portrayal of his life on the track, what a tough driver he was. And that it seems to have touched lots of people who normally can't stand sport."

The film has been a labour of love for Kapadia, who first sat down to discuss the prospect with Ayrton Senna’s family in 2004. And when Formula One boss Bernie Ecclestone unlocked the doors to motor racing’s film archive, it meant hundreds and hundreds of hours of revelatory footage for Kapadia to wade through, and months more of selecting and editing it into just two hours of finished product.

Of course, with so much acclaim, Kapadia's film about Senna is now both explaining the myth of the driver and becoming part of it:

"The filmmakers have now become part of his legend," he agrees, "because Senna's family and fans have loved it and thanked us for showing other people how special he was. So I feel an affinity to Senna, and to his family, his ideals, even to Brazil, that I never had before. It's been an amazing journey for us."

Bizarrely, despite all these hours spent living inside Senna’s head, it was recently that Kapadia actually shared the experience of driving a Formula One racing car, which he describes as suitably bizarre and humbling:

“It is strange that, after so many hours of watching it, we finally got on the track ourselves.

"I think I was the slowest one out there. I was just trying to survive, get from A to B in one piece, and it was still terrifying. And then you remember that these guys are overtaking each other in those conditions, dealing with the G-force, driving in the rain, thinking three turns ahead. Now I’ve sort of experienced the feeling myself, I am even more convinced that professional racing drivers are supreme athletes, that there's something about them that is truly superhuman.”

Senna is on ITV this evening, at 10.35pm.

20 sporting documentaries worth a watch:

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  • Senna

    Spanning the decade from his arrival in Formula One in the mid-80’s, 'Senna' follows the monumental career and tragic death of Brazilian motor-racing champion, Ayrton Senna, taking in his myriad successes and intense rivalry with French driver, Alain Prost.

  • The Class of '92

    This Man-United mega-doc takes a look at the sporting achievements and global superstardom of six superbly talented young Manchester United footballers (David Beckham, Nicky Butt, Ryan Giggs, Paul Scholes, Phil and Gary Neville). Spanning 1992 to 1999, 'The Class Of ’92' covers the players' highs and lows in this golden age of football.

  • Bigger Stronger Faster

    'Bigger, Stronger, Faster' is an astute look at the world of performance-enhancing drugs, and the athletes that rely on them. The film follows three brothers, all either current or recovered users of steroids. Director Christopher Bell explores America’s win-at-all-costs culture and the hypocrisies that pave the way to success

  • Beyond The Mat

    Director Barry Blaustein explores his passion for professional wrestling, leading him on a three-year homage to the United States, on a quest to unravel the mind-set of participants of this extreme sport. With the focus fixed on wrestling stars, Mick Foley, Terry Funk and Jake Roberts, 'Beyond The Mat' is a heartfelt look at a sport at odds with its contemporaries.

  • Bobby Fischer Against The World

    'Bobby Fischer Against The World' offers a fascinating insight into the world of competitive chess. At the centre of this gaming documentary is the captivating life of Bobby Fischer, the first rock star of chess and later a tragic figure.

  • Deep Water

    In 1968, the Sunday Times ran an ambitious competition, challenging amateurs and professionals to complete the Golden Globe Race, a singled handed, round-the-world yacht race, for a cash prize of £5,000. Only one man made it to the end. 'Deep Water' takes us on a journey through the catalogue of disasters that made this one of the most catastrophic boat races in history.

  • Desert Runners

    A complex story of endurance and will-power amongst a team of diverse non-professionals, 'Desert Runners' witnesses a group of amateur athletes as they complete an ultra-marathon across some of the World’s most brutal landscapes.

  • Dogtown & Z Boys

    Narrated by Sean Penn, award-winning 'Dogtown and Z-Boys' tells the story of 8 Santa Monica teenagers, who, shunned by their contemporaries, go on to define a generation of skating during the 1970s.

  • Fists Of Freedom

    One of the most political moments in sporting history.'Fists of Freedom' is a documentary that examines the events leading up to and during the 1968 Summer Olympic Games in Mexico City that led to that moment on the podium. With interviews from athletes including John Carlos, Tommie Smith and activist Dr. Harry Edwards, explaining their motivations and the consequences.

  • Hoop Dreams

    This engaging and, at times, heart-breaking documentary follows two inner-city Chicago natives, Arthur Agee and William Gates, as they follow their dreams to become basketball superstars. As one climbs the ladder of success, the other’s dreams are quashed. This is a suspense story with top notes of joy and an underlying stream of tension.

  • Murderball

    Warriors in wheelchairs, 'Murderball' documents the rough and tumble world of Para Rugby. Through the eyes of the US Olympic team, Murderball combines the high adrenaline of this hardcore sport, with a candid look at disability.

  • On Any Sunday

    1971’s 'On Any Sunday' is a classic for fans of motorcycling. With interviews with some of the sport’s most recognisable practitioners, including the legendary Steve McQueen, the documentary takes an adrenaline-fuelled look at the riders who devote their lives to the racing tracks and off-road courses across the globe.

  • Pumping Iron

    The 1977 doc follows a musclebound young Austrian, Arnold Schwarzenegger, on his quest for glory in the 1976 Mr Olympia competition. The villain of the piece, Schwarzenegger, is filmed psyching out junior rival, Lou Ferrigno, to secure victory.

  • The Endless Summer

    Cult classic 'The Endless Summer' sees Bruce Brown follow two young surfers on their quest for the perfect wave. The journey trails the intrepid surfers as they scale the unchartered waters of West Africa, shark-infested seas of Australia and the tropical tides of Tahiti.

  • The Other Dream Team

    'The Other Dream Team' covers the incredible triumph of a Lithuanian basketball team who, despite numerous hurdles at the hands of Soviet rule, go on to triumph at Barcelona’s 1992 Olympics, and in the process provide a symbol of hope for the Lithuanian independence movement.

  • Touching The Void

  • Tyson

    Mike Tyson takes on his detractors by painting himself as a misunderstood outsider in this self-narrated documentary made up of original interviews and archival footage.

  • Undefeated

    Another Academy Award winner, 'Undefeated' is the ultimate underdog story about a school football team who, against all the odds, and with a record number of losses stacking against them, go on to become champions under the guidance of coach Bill Courtney.

  • Venus And Serena

    'Venus and Serena' offers an intimate look into the lives of two of tennis’s most controversial players during one of the most difficult years of their lives.

  • When We Were Kings

    This Academy Award-winning look at the infamous ‘Rumble In The Jungle’ between Muhammad Ali and George Foreman (he of the grills) with 1974 feature celebrity interviews from James Brown, Jim Brown, B.B. King, Norman Mailer, George Plimpton, Spike Lee and Thomas Hauser.