The ruling this week from the Government's organ donation task force has underlined the importance of patient consent in medicine. In recommending against the opt-out system favoured by Gordon Brown, the panel has argued that such “presumed consent” could undermine trust in doctors.

While this column has supported opt-out donation, I understand this conclusion. It is at least worth trying other ways of making more organs available for transplant, such as a national co-ordination network, before resorting to a change in consent law.

Organ donation, though, is not the only field of medicine in which consent can be contentious. On the day the task force report was published, Harry Cayton, the new head of the Government's health information watchdog, attacked revised consent rules for medical research as “ethically unacceptable”.

Under the new NHS constitution, scientists will be allowed access to health records to identify suitable participants for their research. They may then directly invite individuals with diabetes, for example, to take part in trials of a new drug, without using doctors as intermediaries.

To Cayton, this is an invasion of privacy and another threat to trust. Patients could be upset that a stranger has viewed an intimate medical history, which might include a sexually transmitted disease or depression. Letters of invitation could also be opened by relatives, revealing embarrassing information.

At first sight, these objections seem fair. Confidentiality and consent are central to research ethics and should not be watered down lightly. Yet significant safeguards are in place and, balanced against what patients have to gain, the risks are not great. First, no patient will be compelled to take part in a trial: all that changes is the invitation procedure. Scientists who use the system will be bound by the same confidentiality rules as doctors. Unauthorised use of patient information will be a serious professional offence. Some of Cayton's privacy concerns, too, are not new: letters from doctors can also be opened by the wrong person.

Furthermore, Sir John Bell, of the Academy of Medical Sciences, points out that experience suggests that few patients mind being contacted about research. A project called the UK Biobank, a genetic database, is already authorised to recruit participants directly. In the past six months, one million have been approached; only 20 have complained. This minority's concerns should be addressed, but a simple solution is available. Here, an opt-out facility is the way forward, which would clearly identify those who are certain they do not want to be considered for trials.

For most patients, though, this scheme should be welcome because participating in trials is much more than a public-spirited thing to do. Such research is critical to the development of therapies, and will be streamlined by the new rules. But it also delivers improved care to its participants, and not just through early access to the latest drugs. Trial subjects tend to do better than patients receiving standard care, even when placed in the placebo arm. Their very enrolment seems to make a difference, perhaps because of the closer medical monitoring.

Cancer charities understand this and encourage patients to sign up for trials, with the result that more than one in ten are already involved. Similar participation levels, however, are much harder to achieve for illnesses that require only GP or out-patient care.

The new system should improve matters, putting scientists in charge of trials in touch with patients who can benefit from them. Those patients will still have the final say about whether or not to enrol. It is best understood not as a weakening of consent, but as an extension of opportunity. Nothing is ethically unacceptable about that.

Mark Henderson is Science Editor of The Times, and won the Consumer News and Story of the Year categories at the 2008 Norwich Union/Medical Journalists' Association awards

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