This review is edited and expanded from a first reaction festival blog post on

If THE ARMSTRONG LIE reveals anything about documentary filmmaking, it’s about the need for surprise.

Alex Gibney’s film about disgraced cyclist Lance Armstrong has everything you could possibly ask for, bar that one crucial ingredient: a compelling subject who isn’t all they seem, writing themself a hero’s journey of which Joseph Campbell would have been proud, only to have it up-ended as Gibney's cameras are rolling, to their eventual public disgrace and potential ruin. THE ARMSTRONG LIE’s only real unfortunate flaw – through no-one’s fault - is timing: it arrives when Armstrong's saga is no longer hot news, but nor is it yet a forgotten story with a new revelation.

Most people will know that Armstrong beat his advanced cancer and went on to win (with sensational illegality, as it turned out) the Tour de France seven times, before retiring from the sport in 2005. Doping allegations were already circling Armstrong in 2009, when Gibney began filming what both thought would be the story of Armstrong’s big comeback. In 2010 – just as the filmmaker thought he was finishing up - one of Armstrong’s former teammates made a formal allegation against him. The avalanche of evidence that followed finally engulfed Armstrong in June 2012. By January 2013 it was all over, and before America/Oprah, he publicly admitted his guilt (Gibney's camera were just out of shot as that famous interview took place). The filmmaker was virtually back to square one, but perhaps in rare moment of empathy, or perhaps sensing an opportunity to spin the story one more time, Armstrong granted Gibney one more interview; with nothing more to lose, the master liar promised to tell the whole truth.

You might expect the limit of THE ARMSTRONG LIE’s interest to end with that rather short interview, but Gibney’s remarkable skills as a filmmaker deliver more – maybe not a cannot-look-away masterpiece, but a interesting hero-becomes-villain switcheroo nonetheless. Don’t expect too much of the why (although those few minutes of final confession are impressive), but watching the way he did it - that web of lies growing strand by strand, being held together by a personally enforced omerta, and executed by sheer will of (to all outward appearances) his sociopathic personality, is still pretty fascinating.