Defence Secretary Philip Hammond admitted today that Britain can't hand over people captured in Afghanistan to the country's spooks because they risk being tortured.
A High Court judge was told that the decision had been made on secret new evidence.
The Afghan National Directorate of Security (NDS) is notorious for treating prisoners badly.
The admission came during a court case brought by Afghan farmer Serdar Mohammed, who was taken by British troops in April 2010.
He alleges that the NDS tortured him into falsely confessing that he was a Taliban member.
The case will return to court next week to consider whether Mr Mohammed's arrest and torture violated European human rights law.
Attacks such as yesterday's horrific murder in Woolwich didn't happen before the 'war on terror.' It's time we recognised the consequences of the conflicts we've unleashed