I’ve been watching the Tour de France for as long as I can remember. Back in the eighties, I readily adopted the new sports that Channel 4 brought to air – cycling, NFL, although perhaps not kabbadi. I certainly remember seeing Greg Lemond beat Lauren Fignon in a final stage time trial in 1989, to win the Tour by 8 seconds. But as I was watching Alex Gibney’s new film on Lance Armstrong last night I was trying to work out when I’d ever seen Armstrong in the flesh.

I came to the conclusion that despite all those “victories”, I’d only actually seen Armstrong once. I’d arrived in the French Pyranees on the day of the 15th stage of 1995’s Tour de France. It was the day that young Italian rider Fabio Casartelli died after crashing on a mountain descent.

The following day, I was in Pau as a neutralised race arrived at the finish line, Casartelli’s Motorola team-mates riding ahead of the peleton to salute their fellow rider. Lance Armstrong was one of those team-mates, alongside his good friend Frankie Andreu. That’s the picture you can see above.

So somehow I never managed to see Armstrong ride competitively live. But he’s a man who’s career I’ve always followed assiduously. While I might not have been a “Team Lance” advocate – never having read one of his best-selling books, or ever buying a Livestrong band, preferring to support charitable causes in different less overt ways – I still followed Armstrong assiduously. I wasn’t “inside cycling” enough to realise quite what a nasty piece of works he could be. I was of the belief – the Armstrong lie – that a cancer survivor like him surely wouldn’t mess around with his body after surviving that? How naïve. It was the slow ebbing out of information and admissions that saw me realise my mistake.

When I looked at IMDB to see Gibney’s prolific output, I wasn’t too sure how good The Armstrong Lie could be. Only last year he made the excellent Mea Maxima Culpa, and he’s been directing and producing several documentaries a year in recent years. Can one director maintain the quality with his volume of output?

And given the fact that Armstrong was far bigger than cycling in his homeland, was this documentary going to leave the cycling aspect behind?

I need not have worried.

Gibney presents a thoroughly engrossing two hours built around several interviews with his subject. He’d began making a film about the man back in 2009 when Armstrong had decided to come out of retirement and return to the Tour de France. Gibney’s cameras followed him that year, getting intimate behind the scenes access and the daily thoughts of Armstrong. At some stage though, that film began to fall apart as Armstrong faced mounting accusations from former team-mates like Floyd Landis. And so the film was never completed.

Gibney returned to the film when Armstrong, in the face of over-whelming evidence against him, decided to make a televisual confession with Oprah. Gibney got back in touch with his subject, and was alongside Oprah’s crew as he made his admission in January this year. Gibney interviewed Armstrong himself just after he’d recorded with Oprah. A couple of months later, he got another interview with his subject – probably the best of the bunch.

This documentary is built around this series of interviews as Gibney weaves through the claims and counter-claims, the lies and and the accusations. He doesn’t seem to be limited in the footage that he’s collated, with lots of Tour footage from US and UK coverage, as well as video testimony from Armstrong and others.

He also has extended interviews with former team-mates including George Hincapie and Frankie Andreu, as well the latter’s wife, Betsy Andreu. He even, remarkably, has an interview with Dr Michele Ferrari from 2009 before emails revealed that Armstrong was still secretly working with him. Of the major players who are talking, Tyler Hamilton is probably the obvious face that’s missing.

We also hear from the journalist David Walsh, who has faced legal action on multiple occasions over the years. Some of the unedited press conference footage in which we hear his voice, as well as that of fellow journalist Paul Kimmage, is very enlightening.

This is all beautifully weaved together with good use of graphics, and cross-cutting between participants. This isn’t an easy story to tell properly, and you could easily get bogged down in some of the detail, but Gibney keeps things moving.

And the closing line, which Gibney has caught in his January 2013 interview with Armstrong, is fascinating. I won’t spoil it here.

The film does leave question marks over Gibney’s own views. He’s quite self-critical during the film, particularly of the “Go Lance” attitude he was taking during the 2009 Tour. He’s aware that he was getting sucked into Armstrong’s narrative – that his film could be seen as extending the Lance myth. On the other hand, Gibney still thinks that in spite of everything Armstrong is an exceptional athlete. That’s probably true. He has the view that since everyone was doping at the time, the record books should read Armstrong* rather than being left blank.

I’m not sure that’s a viable answer. That’s expecially the case since the film includes the sequence during which Armstrong needlessly chases down Felippo Simeoni and explicitly gestures for him to zip it and maintain the omerta. Not every rider was on drugs. And Gibney hints that Armstrong did something even during the Tour he followed him on, when large parts of the sport had definitely cleaned up.

And Gibney is aware that he might still be helping perpetrate the Armstrong myth by making this film with the interviews that Armstrong has offered. Although revealingly, he says that he stopped staying in touch with Armstrong after telling him what he was calling the film. Armstrong has yet to see the film, although his “people” have seen it.

All told, a genuinely enlightening film that does add to what we know of the story. I’m not sure yet when the UK release date will be.

[Update] According to Empireonline its UK release is 31 January 2014. And there’s a nice picture from the set of a new Lance Armstrong drama directed by Stephen Frears.