The seriousness of this weekend's allegations that British intelligence services might have been involved in the rendition of Libyan nationals cannot be overestimated. There is said to be specific documentary evidence that our officials made direct requests to the Gaddafi regime for "timely detainee debriefs" on people they knew would have been tortured. British officials are also accused of passing information to the former dictator about Libyan nationals living in the UK. It is quite possible that some of these people were put under surveillance and subjected to control orders as a result of information obtained by "interrogation" of those held in Libya's notorious prisons.
In the wake of this, one thing all seem to agree on is the need for a thorough independent investigation. The Prime Minister says that the Detainee Inquiry into allegations of British complicity in torture, led by Sir Peter Gibson, is the proper mechanism for this. But the fact is that these disturbing allegations only serve to highlight the inadequacy of the Gibson process.
It might be thought that claims of systemic involvement in torture merit a full judicial inquiry - after all, if phone hacking by journalists does, then surely this does. But unfortunately the so-called Detainee Inquiry, as currently proposed, looks more like a secretive internal review.
The Evidence Protocol for the inquiry, published in July this year, makes it clear that there will be a presumption that secret documents remain so, and the crucial final word on whether material can be made public rests not with Sir Peter but with the Cabinet Secretary, the Government's chief civil servant. Further, it has been confirmed that the only involvement of the detainees themselves would be in submitting a statement of their allegations. They will not see the majority of the government's evidence and will not be allowed to put questions to those allegedly complicit in their abuse - even by way of their legal representatives. These fundamental flaws have led all non-governmental organisations working on these issues, including Liberty, and the detainees themselves, to boycott the process.
So, unless there is a wholesale rethink of the Detainee Inquiry, it cannot possibly achieve the original aims of getting to the bottom of what happened and restoring the reputation of our security services. Frankly, it is hard to see the point of wasting precious public money on it.
What is urgently needed is a credible, transparent investigation which commands public confidence and can establish either that none of the allegations are well-founded, in which case politicians and security officials can hold their heads high and move on, or make findings as to what, how and why things went so wrong, identifying lessons to be learnt and hopefully ensuring that British authorities are never involved in such shameful practices again.
These latest allegations also introduce a new imperative. A senior member of the rebel military forces which overthrew Gaddafi is demanding an apology from the British government for his mistreatment. It is not only the damaged reputation of British intelligence officials we need worry about now; it may also be the future relationship of the UK government with new, hopefully democratic, regimes in the Middle East. The Coalition Government should now make this a top priority.