''Governmental and medical bodies have begun adjusting and blurring their ethical guidance, tilting themselves towards endorsement of gross ethical malpractice, thereby ensuring the continuation of doctors' involvement,'' Michael Wilks, the BMA's ethics committee chairman, said in the latest issue of the medical journal The Lancet.

The issue received some media attention amid reports last year that prisoners had been abused at U.S. detention centers at Abu Ghraib, Iraq, and Guantanamo Bay, Cuba. But ''the involvement of doctors in torture and the abuse of prisoners' human rights has been well documented over the past few decades,'' Wilks said.

He urged a series of steps to ''reverse this corruption of ethics.''

National medical associations need to tighten their ethics policies and bring to book individual members found in violation. Likewise, international bodies such as the World Medical Association, scheduled to meet in October, must hold accountable their national chapters for failing to quell abuses, he said. Additionally, he called on the United States, Britain, and their allies to reverse what he termed their assault on the United Nations.

Wilks, citing media reports, a U.S. government report, and a leaked report from the International Committee of the Red Cross, said that at Abu Ghraib and Guantanamo Bay, ''medical personnel failed to report evidence of torture, failed to intervene to stop it being repeated, and made available to interrogators information from confidential medical files, thereby allowing interrogators to exploit weaknesses.''

The incidents likely ''represent isolated, rather than endemic, patterns of behavior by U.S. military doctors,'' Wilks acknowledged.

Even so, he said, ''the involvement of doctors in the direct or indirect abuse of prisoners is not just a stain on medical ethics. By abandoning our principles, we add fuel to the fires of distrust and despair.''

In his view, U.S. medical bodies have failed to take adequate steps to resist backsliding on ethics.

U.S. professional institutions failed to protest when the administration of President George W. Bush declared in February 2002 that the Geneva conventions would not apply to al Qaeda terrorists, he said. They held their fire again in August that year, when the administration issued a memo stating that ''physical pain amounting to torture must be equivalent in intensity to the pain accompanying serious physical injury, such as organ failure, impairment of bodily function, or even death.''

According to Wilks, ''this failure to oppose put prisoners, already incarcerated without trial or access to legal representation, at the mercy of unprincipled doctors.''

''This inertia is bad enough, but there is evidence of a more worrying trend--governments and professional bodies rewriting existing ethical guidance in the service of abuse,'' Wilks charged, citing research by groups including U.S.-based Physicians for Human Rights.

Wilks urged ramped up ethics lessons in medical school and tighter codes of conduct for healthcare professionals' associations.

''The problem is that published codes are strong in their application with the one-to-one relationship with patients, but weak when applied to communities, and therefore open to distortion and misrepresentation,'' Wilks said. U.S. defense officials, for example, have said that ''physicians assigned to military intelligence have no doctor-patient relationship with detainees and, in the absence of life-threatening emergency, have no obligation to offer medical aid.''

These personnel are not answerable to the Department of Defense but to military intelligence and work within Behavioral Science Consultation Teams commonly known as ''Biscuits.''

In new guidance issued to the military, the Pentagon has subtly changed the wording of a 1982 United Nations resolution on the ethical duties of health professionals with respect to prisoners, he said by way of an example.

Similarly, he assailed the American Psychiatric Association's Statement on Psychiatric Practices at Guantanamo Bay as ''weak.''

He singled out for special criticism a recent report of the American Psychological Association's Presidential Task Force.

''This report rehearses conventional ethical principles about care of individual patients, but then does an about-face when it comes to sanctioning input from psychologists and advice on techniques to be used in interrogation,'' Wilks said. ''In effect, it becomes acceptable for a health professional to dispense with any ethical responsibilities when their training and expertise is used outside a strictly therapeutic context.''

''The use of such knowledge in creating techniques intended to damage the minds of people under interrogation, and to advise how these techniques can be refined, is grossly unethical, and the fact that a professional body can support such activity is a disgrace,'' he said.