If MI6 did the work of Libyan renditions, who gave the orders? What sort of ethical standards should we expect of the intelligence and security services? That's one question raised by the investigations into whether or not MI5 and MI6 have been involved in torture: not actually doing it themselves, but making it possible for others to do so. Keir Starmer, the Director of Public Prosecutions, announced last week that the police had begun a criminal investigation into MI6"s conduct in facilitating the "rendition" of two Libyans back to Libya in 2004. The unusual aspect of the case is that MI6 wasn't trying to help the US government: it was working with Col Gaddafi's regime. When he fell, and the offices of his intelligence service were pillaged, a letter from Mark Allen, an MI6 officer, now Sir Mark, was found. In it, he congratulated the then head of Libya's intelligence service on the safe arrival of a dissident, Abdelhakim Belhadj, whom Gaddafi's henchmen had long wanted to imprison. In words which seem to indicate that MI6 facilitated the poor man's passage, Mr Allen added that it was "the least we could do for you and for Libya to demonstrate the remarkable relationship we have built over the years." Since Mr Belhadj was tortured, this makes you wonder what MI6 was doing helping the Libyan intelligence service get their blood-stained hands on him. MI6 knew perfectly well that Gaddafi's regime was brutal and merciless. Collaborating with torturers might conceivably be justified when it will save lives. But Sir John Sawers, the head of MI6, has unequivocally rejected that argument, saying that "torture is illegal and abhorrent under any circumstances, and we have nothing whatsoever to do with it. If we know or believe action by us will lead to torture taking place, we're required by UK and international law to avoid that action. This merely deepens the mystery of what MI6 thought it was doing collaborating with Gaddafi's intelligence service, which they must have known very well tortured people with casual insouciance. Perhaps a huge pay-off in terms of life-saving information convinced Sir John's predecessor that it was worth it - although that is not easy to believe. How could MI6 trust anything that came through the Libyan intelligence service, the organisation that planted the bomb that blew up over Lockerbie? Moreover, Mr Belhadj does not seem to have been an al-Qaeda fanatic. His crime seems to have been to oppose Gadaffi. He is now an official in the new Libyan government. Sir John Sawers has also said: "Ministers tell us what they want to know, what they want us to achieve. We take our direction from the National Security Council. When our operations require legal authorisation or entail political risk, I seek the Foreign Secretary's approval in advance. Sending dissidents to Libya to be tortured would surely "entail political risk." So why would any minister order it? In 2004, Tony Blair's new ally was Col Gaddafi, who announced in late 2003 that he was ending his programme to acquire nuclear weapons. Mr Blair wasn't slow to claim the credit for that, and for bringing Libya into the "community of responsible nations." Might he, conceivably, have asked MI6 to co-operate with Gaddafi's thugs to further that relationship? If so, that would be outrageous. Mr Blair denies he did any such thing. MI6 will be forgiven for lapses from the highest ethical standards when it is necessary to prevent mass murder. But colluding in torture merely to smooth diplomatic relations does not fall into that category. Mr Starmer rightly says the allegation is "so serious" that the investigation must start immediately. But if it targets MI6 officers, and not the ministers who set the policy, it will lead nowhere. It won't bring justice, it won't tell us what really happened and it won't improve ethical standards. It will merely be another example of failing to meet them.