Presumably Derek Keilloh swore a version of the ancient Hippocratic Oath when he qualified as a doctor.

It will have included a promise to treat his patients with dignity and respect, to do good and not evil, to provide a good standard of care and to act with honesty and integrity. His actions in Iraq, where he served as a medical officer with the First Battalion Queen's Lancashire Regiment, were a cruel mockery of that oath on every level.

Baha Mousa, the hotel receptionist beaten and tortured to death by British troops in Basra in September 2003, was later found to have 93 injuries. His own father did not recognise him. Nobody who has seen the image of Mr Mousa after his death is likely to forget it. Yet throughout a series of courts martial and a subsequent public inquiry, this doctor swore under oath that he saw no injuries to Mr Mousa's body beyond a little dried blood around the nose.

Yesterday Dr Keilloh, originally from Aberdeen but now working as a general practitioner in Yorkshire, was found guilty of "misleading and dishonest" conduct. The Medical Practitioners Tribunal Service ruled that he knew the dead man's condition but did not report it to senior officers or assess other detainees and protect them from further mistreatment. The General Medical Council must now decide on what action to take. Options include suspending him or striking him off, if it decides his behaviour amounted to misconduct. If the GMC fails to make an example of Dr Keilloh, it will send out the message to other army medics that normal conduct is suspended during war operations and they are free to turn a blind eye to anything. That would be a travesty of justice.

Context is important. These suspects turned out to be innocent civilians whose weapons were intended to defend hotel guests, but a rumour had circulated in the British regiment that they had murdered members of the Royal Military Police. There was fear and anger and the detainees were supposedly being "softened up" for questioning. However, that is no excuse for the soldiers' subsequent thuggery and collapse of discipline. Dr Keilloh was the one man on the spot who could have stopped it but, as one survivor put it: "He heard our cries and he didn't do anything."

Just 28 years old and only eight weeks into the job, he may plead inexperience but his failure to intervene during or after these events amounts to collusion. Army medics cannot afford to be squeamish but ignoring such brutality amounts to a betrayal of all the servicemen and women who behave decently and within the rules. It also acts as a recruiting sergeant for extremism and destroys at a stroke any goodwill built up with the local population. It is shameful that it has taken so long to uncover the truth. Though maltreatment of detainees may not have been routine, the fact that a number of other such inquiries are still crawling through the system suggests this was more than the work of a "few bad apples". It is also disturbing that the Justice and Security Bill, currently going through Parliament, is likely to make it harder than ever to get to the truth in such cases.