Commissioned by the BBC for exposure via the organisation's internet television service iPlayer rather than conventional broadcast, this idiosyncratically illuminating study of disastrous foreign entanglements in Afghanistan will doubtless make waves on both big and small screens overseas following its world-premiere at Rotterdam.

Epic in scope at 137 minutes, it's an accessible primer on recent world history which could easily warrant theatrical distribution in numerous territories, if appropriate rights issues can be negotiated.

Politicians used to have the confidence to tell us stories that made sense of the chaos of world events. But now there are no big stories and politicians react randomly to every new crisis - leaving us bewildered and disorientated.

Bitter Lake is a new, adventurous and epic film by Adam Curtis that explains why the big stories that politicians tell us have become so simplified that we can’t really see the world any longer. The narrative goes all over the world, America, Britain, Russia and Saudi Arabia - but the country at the heart of it is Afghanistan. Because Afghanistan is the place that has confronted our politicians with the terrible truth - that they cannot understand what is going on any longer.

The film reveals the forces that over the past thirty years rose up and undermined the confidence of politics to understand the world. And it shows the strange, dark role that Saudi Arabia has played in this. But Bitter Lake is also experimental. Curtis has taken the unedited rushes of everything that the BBC has ever shot in Afghanistan - and used them in new and radical ways. He has tried to build a different and more emotional way of depicting what really happened in Afghanistan. A counterpoint to the thin, narrow and increasingly destructive stories told by those in power today.