The rule of law has become a constitutional treasure in Britain because it has managed over the years to deliver an appearance of legality without threatening to destabilise the exercise of raw executive power. Judges have held ministers to account on matters of no great importance - but they always used to run for cover if the magic formula 'national security' was so much as whispered in their presence. Unions have been banned (at GCHQ), internment imposed (during the Second World War), political parties censored from the media (Thatcher's ban on Sinn Féin), CND protesters prosecuted under the official secrets act - and all with the enthusiastic endorsement of successive generations of judges who saw themselves (almost unashamedly) as the iron heel (as Jack London put it) with which brutally to stamp out dissent. The last of these regiments of yes-men were the generation (Lane, Donaldson, Bridge, Denning et al) who saw it as their duty to make sure that any Irishmen brought into their courts, on any count, stayed in the jails to which the police had consigned them - regardless of how obviously ill-treated they had been, or otherwise vulnerable. What a change we have seen! Binyam Mohamed's case was before the three most senior judges in the land outside the Supreme Court. None of the three is anything other than mainstream: their views can be taken reliably to reflect the atmosphere that prevails in the rarefied judicial world in which they spend their professional lives. Their decision upholds the principle of open justice as against the interests of the intelligence service and requires that the full basis for Binyam Mohamed's victory in the lower court is made clear to him. The fact of the US maltreatment of him, and of the UK's knowledge of and possible collusion in such treatment, was not to be covered up to protect the interest the state's intelligence service has in maintaining good relations with its counterparts in the US: we are talking, after all, of solidarity between torturers, not ordinary state servants.

Why the remarkable change in judicial attitudes? The end of the Cold War has certainly played a part: the future of the state no longer seems to require swallowing any old assertion by this or that spy about what security requires. Nor does a colonial mentality any longer pervade the bench: the Iraq invasion genuinely appalled the judges, not only on account of its illegality (which was plain to all but one or two legal advisers - on whom, needless to say, the government immediately relied), but also because of its casual, imperialistic brutality. This is a bench reared on talk of human rights, aware of its own relative good fortune and open to the kind of empathy with others that a human rights culture was intended (by this government no less!) to stimulate. The authorities had hoped to keep their (public) ideals well away from their (private) practice - how sad that this is how Labour (eventually) and Obama (almost immediately) have ended up, and that decent progressive people need to rely on judges to expose the immorality of state agents serving supposedly left-of-centre governments.