The Commentator has published a piece of mine – Torture versus terror – a tale of two resignations – which is intended to bring out in 100% unambiguous terms what practical and ethical/policy dilemmas a blanket extension of the idea of ‘complicity in torture’ might produce.

It takes a dramatic imaginary scene some years in the future to explain why and precisely how some anguished operational choices might need to be made, and how different honourable people might come to completely different conclusions:

I believe that in the extreme circumstances I faced, I acted – as I was elected to do – in the national interest, by accepting that information and acting on it. Torture is despicable. We work tirelessly at the United Nations and elsewhere to stamp it out.

But I believe that it cannot be right to avoid any action to thwart murderers and so save innocent lives. The relatives and friends of all the victims of the bombings today in London and Edinburgh will be tortured by their grief from this disaster every day for the rest of their lives.

This situation creates appalling policy and ethical dilemmas for us all. Indeed, I myself might be open to prosecution for what I did. If this happens I will plead not guilty but enter no defence and leave it to the jury to decide.

I do not wish to continue to serve as Prime Minister without a clear mandate from voters as to how I should respond in such circumstances.

I hereby resign my seat in Parliament with immediate effect. A by-election will be called in the shortest possible time. I will stand for re-election but not campaign for it. My statement here tonight represents my only policy position and my only public statement in that campaign…

In fact the dilemmas are there already for practical purposes. British police officers have been busy grilling MI6 officers on what if anything they knew or suspected about the treatment in other countries of AQ and other terror suspects.

These issues take us right to the very outskirts of Policy and how it’s made. And if you want one of the most remarkable and profound set of answers ever articulated on some of these problems as they come up in a democracy out there on the Limits of Diplomacy, swing by the transcripts of the UK’s Iraq Inquiry and have a read of this testimony by an MI6 officer.

Plenty of heavy black redactions for reasons of the highest secrecy, but what’s left is gripping and subtle enough. And, in parts, downright magnificent:

Did you have much contact with Alastair Campbell through this period or generally?

SIS4: I never met him. I saw him across the Cabinet room table on the morning after 9/11 and I didn’t know who he was. I had to ask.