Seven out of ten people say that they support the idea of donating an organ to save other lives. But in practice, only one in four has actually joined the NHS donation register. Whether this is due to squeamishness or inertia is not clear. But the gap has become the subject of fierce debate. Sir Liam Donaldson, the Chief Medical Officer, argued yesterday that all people should be treated as potential donors unless they explicitly opt out of the register, because too few currently opt in. Around 400 individuals die each year waiting for an organ transplant. Every single one of those lives is precious. But so, too, is control over one’s body.

There are too few organs to meet current need, but this cannot be blamed solely on public meanness. Since the organ donation register was established in 1994, the numbers signing up have grown steadily. Today there are 14.5 million signatories, almost a quarter of all adults. That is a very considerable and honourable number.

The demand for transplants is outpacing donors: it has increased by 30 per cent in the past five years, chiefly due to diabetes and obesity. Six thousand of the 7,000 people waiting for transplants are waiting for a kidney. Some black and South Asian groups also suffer disproportionately from kidney problems, and these groups are also more reluctant to donate. Although a third of kidneys are provided by living donors, the donations simply cannot keep pace.

What should be done? With today’s medical technology, it seems outrageous that so many people die needlessly. But not everyone believes that presumed consent would solve the problem. The National Kidney Federation says that even a surge in donors would not lead to a dramatic increase in transplants, because the NHS lacks sufficient surgeons and intensive care unit beds to deal with them.

Another reason is the safeguards which, rightly, ensure that organs are taken only from patients who have absolutely no hope of life. Two doctors must certify that the potential donor is brain-dead. They also ask the permission of the next of kin. This is one of the biggest barriers to increasing transplant numbers. Four in ten relatives currently refuse permission. This is not entirely surprising. Far too few people ever discuss their wishes with their nearest and dearest, leaving grieving relatives to make agonising decisions against the clock. At the moment, those who want to sign up can do so voluntarily at www.uktransplant.org.uk. Perversely, a policy which assumed that all people had consented unless they opted out could make it even harder for families to gauge patients’ wishes.

Much more should be done to encourage people to sign. Those who apply for a driving licence are asked to tick a box, and GPs should do the same when patients first join a new surgery. Life insurance companies could include a box on their application forms. More could also be done in hospitals. Spain has run a successful opt-out programmes with widespread public support. But the higher rate of Spanish transplants seems to be due not only to higher numbers of donors but also to the employment of powerful hospital transplant co-ordinators, who give the efficient use of organs the highest priority.

Everything possible should be done to encourage people voluntarily to donate their organs when they die, and to use organs efficiently. But our bodies should not be nationalised on death, and they do not need to be.