It's funny watching the elements come together in this complicated scam. On one hand, the set-up isn't quite as complex as it seems, but there's an easy sense of fun in every exchange.

This is a must-see and one of the best documentaries - and films - of this year.

I think this is a new genre that they're all sort of working their way through it and haven't got all the kinks worked out yet but it's a genre that works for me.

The film never slows down or bores, plunging from one harrowing sequence to the next.