Hilary Andersson investigates numerous allegations of recent physical and mental abuse of prisoners held at the detention centre at the US military's Bagram Airbase in Afghanistan.
The centre became notorious during the early years of the American operation in Afghanistan, with well-documented cases of torture.
Conditions improved and President Obama came to power promising to clean up Bagram - and there is now a new detention centre at the base.
Now, there are new allegations that prisoners are again being subjected to deliberate abuse there - including sleep deprivation and extremes of cold.
Many former detainees describe being held in a top-secret dark prison" within the centre, where conditions are particularly harsh.
The US military authorities and the Obama administration deny all these allegations and insist that the detainees are Islamist terrorists who are committed to violence.
And Hilary investigates cases of "extraordinary rendition" by British authorities, where detainees were transferred from Iraq to Bagram, even though there was clear evidence that they were at risk of torture.
She discovers that one of the detainees has become insane while held in Bagram.
Why did the British government do this and why is it not seeking the men's release?
Producer: Caroline Finnegan.
Hilary Andersson investigates allegations of recent abuse at the US-run Bagram Airbase."