Andy Hull [Senior Research Fellow, Institute for Public Policy Research]: "Both the UK's domestic Security Service (MI5) and its overseas Secret Intelligence Service (MI6) are being investigated by London's Metropolitan Police to see if British agents have been complicit in torture.

I am reassured by contacts I trust that no British agent has actually committed torture. Some of those same contacts are, however, less convincing when asked whether they believe that in every situation in which a British agent may have had reason to suspect foreign security services of treating a suspected terrorist in a cruel, inhuman or degrading way, they have spoken out against that treatment as forcefully as they might have done, or as forcefully as international law demands.

There is no doubt that in interrogation chambers around the world a golden rule – the absolute prohibition of torture – has been broken. I hope that these police investigations in the UK confirm that none of those charged with protecting us here have effectively stood by in the knowledge that others were breaking that rule.

Civil libertarians cannot dodge an uncomfortable truth. UK intelligence liaison with the likes of the Pakistani ISI has saved British lives. We have good reason to believe that the ISI sometimes torture their detainees. They will always deny that, if asked. Such an intelligence relationship therefore inherently runs the risk of being perceived as – or, worse, actually being – collusive in torture. The only way to avoid that risk would be to terminate the relationship. That could cost British lives.

Security professionals, on the other hand, cannot dismiss or dishonour the considered conclusions of those who, in the wake of the horrors of the Holocaust and the aftermath of World War II, signed the Universal Declaration of Human Rights, which forbids torture without exception.

Stopping bombs while standing up for what we believe in is no simple matter, but, in the end, legitimacy in security policy is a strategic neccesity, not a liberal nicety."