While baiting the General Medical Council continues to be a popular sport, the leading cancer epidemiologists cited in your report ('Cancer experts call for action on GMC's confidentiality rules', news, page 4, 2 November) display the kind of arrogance and disregard for patients' rights that characterised Bristol, Alder Hey and other recent NHS scandals.

They fail to appreciate that confidentiality goes to the root of the patient/doctor relationship and that the right to privacy and confidentiality is enshrined in law, most notably through the new data protection and human rights legislation. Routine, extensive and institutionalised breaching of patient confidentiality is nowhere better exemplified than in the cancer registries.

It is true, as Professor Coleman claims, that no case law exists yet on the Data Protection Act 1998.

However, the act itself is plain that those who collect personal data from patients must inform them of the purposes to which it will be put to enable them to object, and the research exemption does not exempt from this requirement.

Furthermore, Professor Coleman presumes that, before court cases on statutes, rights ostensibly granted do not have to be observed. That is nonsense and exploits the vulnerability of patients by placing the onus on them to defend their rights against breaches that have already occurred, when the intention of the legislation is clearly to prevent breaches in the first place. It is defended on the grounds of 'public interest'. But it is not for researchers to determine what is in the public interest when their own vested interest compromises their integrity in these matters.

The GMC should be applauded for protecting a fundamental patient right. It is also reassuring that some trusts recognise their legal obligations by refusing to co-operate with personal data collection where the patient's consent has not been sought.

It is beyond comprehension that Professor Coleman thinks it 'risible' that patient consent for data collection should be sought.

Cancer patients, throughout their treatment, will be asked for their consent on many occasions. Why is it impossible to obtain it for data collection?

While many epidemiologists and clinical researchers see the obtaining of consent as an irritating inconvenience, it is only the avoidance of that inconvenience, not the importance of cancer research, that is in genuine conflict with confidentiality and privacy.

Professor Coleman implicitly suggests that it is reasonable to flout the law and override patients' rights because some patients who are asked will withhold their consent and thus create bias. What reason is there to believe that those who refuse (I suspect very few) will possess some specific characteristic allied to their cancer diagnosis?

Evidence, not self-serving presumption, is required.

Instead of whinging about quite proper GMC rules on patient confidentiality, Professor Coleman and colleagues should invest a little time devising methods to obtain the consent of patients for personal data collection:

problem solved and patients' rights upheld.

Deryck Beyleveld Professor of jurisprudence Sheffield University, Vice-chair Trent Multicentre Research Ethics Committee, Director Sheffield Institute of Biotechnological Law and Ethics