Much of the time, it's a stupid tactic: readers drift off to something shorter and lighter, audiences fidget and daydream about toilets and G&Ts. But there are times when extreme demands on patience are justified. Claude Lanzmann's Shoah, nine hours of testimony about the Nazi death-camps, is one case in point. Maybe few of us will be able to sit through it without moments of weariness, but that is part of the deal - your discomfort is a gesture of acknowledgement, even expiation.
Something similar is true of Gulag (Sat BBC2), Angus Macqueen's three-hour film about the labour camps of Stalin's Russia. It is an effort to concentrate for all that time, and it doesn't help when, as here, you sometimes need to sit back to try to absorb calculated atrocity. But anything less would have seemed like an insult to the tens of millions - 20 million? Fifty million? Nobody knows - who died in the camps.
And how you could shrink this story into a smaller space? It is hard to appreciate Russia's scale and its effect on people. One woman described being taken away by the NKVD, the secret police who ran the Gulags. Didn't she think of escaping? She couldn't see any point: where was there to run to? You saw what she meant when a former warder sketched the course of the Trans-Siberian railway - thousands of miles long, with camps lining the track either side "like beads on a necklace". He guffawed at the idea that he might have visited them all: 1,000 years wouldn't be enough. Later, the camera panned over one camp, Norilsk in northern Siberia - mile after mile after mile of barracks and factories, on and on into an icy blankness.
The history of the gulags has all but vanished. Again and again survivors and bystanders told Macqueen they didn't want to talk, to think about it. He asked an NKVD man what happened to the prisoners he drove to his headquarters: "Think for yourself" was the reply. A few minutes later, they discussed what might have lain behind a certain door. What did he think?, Macqueen wondered. "I don't think," said the NKVD man.
But there were enough answers to be going on with: living men used to fill a breach in a dam; women raped repeatedly for days on end; limbs jutting from mass graves; and the drawn-out terrors of cold, hunger, fear, a stench of shit, urine and stale blood hanging over everything. Still there were Russians prepared to tell the cameras that it was worth it, NKVD men proud of their achievements. Macqueen caught all the awfulness, but also all the complexities, the nuances of shame and self-justification. Gulag was a difficult film, but also a magnificent, shattering one. Worth every minute.Reuse content