MI5's lawyers had been attempting to overturn an earlier ruling, which had prevented them from suppressing claims of abuse at Guantánamo and other overseas prisons used in the 'War on Terror'.
Reprieve's Director, Clive Stafford Smith described this legal fight-back as 'wonderful', and expressed hope that the UK's governing parties stick to the principles which they voiced in opposition:
“The first casualty in the 'War on Terror' certainly was the rule of law, but it is wonderful to see the law fighting back now," he said. "One must hope that the Conservatives and Liberal Democrats, having been so critical of this kind of infringement of our liberties while in opposition, will maintain that position now they are in power."
For further background, see the Supreme Court's press summary of their judgement.