Ignorance, they say, is no excuse, but even before the release of thousands of Pentagon documents early this month, we could not have pleaded ignorance about America's detention camp in Guantanamo Bay. In February, a UN report condemned its use of "torture". Amnesty International has called it an "aberration". Our own Commons foreign affairs committee has declared it a hindrance to the war on terror. The Archbishop of Canterbury has accused it of casually overriding habeas corpus. Even Tony Blair has gently hinted that "this anomaly" should close.

We should all, of course, be Jack Bauer when it comes to wanting to get the "bad guys" (a technical term from the lips of George W Bush), but of the 750 who have been held in Guantanamo over the past four years, only ten have been charged, and none found guilty. In a classic case of you-don't-have-to-be-crazy-to-work-here-but-it-helps, the only people who still judge Camp Delta a roaring success are the people running it.

The Telegraph recently reported an enthusiastic US official as saying that a bunch of detainees had admitted to being in contact with last July's London suicide bombers, quite a feat given that they had been in Guantanamo since 2001. He was equally bullish about the means by which other "really significant" insights had been obtained. "The most common method used to interrogate detainees is to sit down with them, watch a movie and eat pizza. You build up a relationship with them and eventually they co-operate," he explained.

Needless to say, movies and pizzas do not feature heavily in Michael Winter-bottom and Mat Whitecross's The Road to Guantanamo (9 March, 9pm), which (after Ishtar) has to be the least amusing road movie ever made. It tells the story of the Tipton Three, a trio of Muslim young men from Tipton in the West Midlands, who made the mistake of travelling to Pakistan in September 2001 and then crossing into Afghanistan just after the US-led invasion. Asif Iqbal, Ruhal Ahmed and Shafiq Rasul spent more than two years in Guantanamo before being released and returned to Britain.

From the moment they were greeted with the words "You are now the property of the US marine corps", their treatment amounted, by any reasonable standards, to torture. At Camp X-Ray, the prototype for Camp Delta, they were kept in open-air cages where they were permitted neither to speak to their neighbours nor to pray. They were brought for interrogation with bags over their heads, told to remain on their knees and kicked when their attention flagged. One of them was chased around a yard by a dog. Another was kept in isolation for three and a half months and subjected to strobe lights and deafening heavy-metal music. Their interrogators repeatedly lied to them, claiming that their friends had shopped them for belonging to al-Qaeda and that incriminating evidence had been found in their homes.

As a journalistic account of their story, The Road to Guantanamo is sober, refusing to stray beyond what the three young men could have witnessed for themselves. As a polemic that might prod sleepy consciences, it is woeful. There is hardly any attempt to humanise the men or distinguish between their personalities (indeed, as the action cuts between the real trio and the actors, with changes in their haircuts and beards, it is hard even to follow who is who).

The only flash of humour is an Ali G moment when one of them invents a rap song about the "retard guards", one of whom appears to enjoy it, up to a point. Yet we are left with no idea of what the three thought about 9/11, the invasion of Afghanistan, America or one another.

We do learn that until Cuba made him into one, Iqbal, at least, was no hero. He had a criminal record in England and had, as it happened, been in and out of court exactly at the time he was meant to be training in Afghanistan. He had travelled to Pakistan because his parents had said it was time for him to get married there. Four days after his arrival he met and approved his bride. Ahmed, Rasul and a third friend, who would vanish in the bombing of Afghanistan, went out as his wedding guests. It would, reasoned Ahmed, be "a great holiday". Why they then decided to cross the border just as Afghanistan was about to be bombed was not satisfactorily explained. The "holiday" was abandoned on the recommendation, it appears, of a mullah at a Pakistani mosque, who was recruiting volunteers for "aid work" in Afghanistan. The film barely debates this momentous, and in one case fatal, decision.

This is not what a standard TV movie would have offered. It would have dramatised Iqbal's falling in love, his painful decision to abandon his fiancee, her dig-nified, Jill Morrell-style campaign for his release, and the stoicism of his puzzled parents, let down by the country they had come to call their own. There would have been appropriate incidental music. Their release would have made us cry. But Winterbottom and Whitecross's film is so flat and unemotive, it is hardly television at all. For goodness' sake, surely the moment for this sort of scrupulous storytelling has passed. We know the truth. We need it to be turned into popular drama.

Andrew Billen is a staff writer for the Times