When a doctor says he has practised mercy-killing, as two GPs did last weekend, it always causes a stir. The BMA makes brave protestations of prohibition, but in truth it goes on all the time. As much as it should? or more so?
For country doctors assisting at home births, it was all in a day's work. As the baby was delivered, out of sight of the labouring mother, the doctor would give it a quick visual check. If all was not in order, the good doctor might seize a pillow, clamp it over the infant's head and say: "I'm sorry Mrs Smith, there seems to be something wrong ..."

Forty years ago such killings were not uncommon. They were widely, if privately, seen as merciful medicine. Today, the focus has switched to the other end of life: how to achieve release from a terminal illness with dignity and peace. At the weekend, two family doctors - Dr Michael Irwin of Hove, Sussex, and Dr David Moor of Newcastle upon Tyne - separately decided to break cover and confess to the mercy-killing of terminally ill patients.

Their intention, they said, was to further the debate on euthanasia. But on close examination little distinguishes their behaviour from that of thousands of other doctors seeking to relieve suffering. It is not what they do, but what they say about what they do that is different. This is an issue that has split doctors and the public; and opinions have, if anything, polarised over the past four decades.

Many searing examples are cited in defence of euthanasia or the closely associated "physician-assisted suicide" (the distinction rests with who administers the final, fatal dose of drugs - doctor or patient). Annie Lindsell, a 47-year-old motor neurone disease patient, is seeking a historic court ruling to allow her doctors to end her life should she reach the point where no treatment can ease her suffering.

The disease, which attacks the nerves, has already left her confined to a wheelchair. She apparently fears it may attack her chest and throat, leaving her unable to breathe or swallow and facing an agonising death by suffocation. The British Medical Association disputes this prognosis and says there is nothing under the current law to prevent doctors prescribing any drug in any quantity necessary to relieve her distress.

One of the most disturbing cases, which jolted the resolve of even the most ardent supporters of euthanasia, involved a Dutch psychiatrist, Boudewijn Chabot, who admitted helping a healthy 50-year-old woman to end her life in 1991. He had agreed with her that she was hopelessly, irretrievably depressed after the loss of her two sons, both of whom died, two years apart, aged 20.

Dr Chabot was charged with malpractice, but acquitted after the judges accepted that a patient's psychological suffering was as valid a reason for seeking euthanasia as physical suffering. Critics, however, saw this case more than any other as exemplifying the "slippery slope" dangers of accepting the practice.

Many doctors argue that patients who ask for death are depressed, even if they deny it - and depression, like pain, can be successfully treated. Others take the opposite view. An Aids specialist said: "Why is it irrational to want to hasten death when one is so ill and has no hope of recovery or release from suffering?" An American survey of 200 psychologists found 81 per cent who supported the notion of rational suicide.

A third case which challenged euthanasia supporters was that of the American Gerald Klooster, an Alzheimer's disease sufferer. His son, Chip, kidnapped his father after he discovered that his mother had sought the advice of Dr Jack Kevorkian, popularly known as Dr Death. Dr Kevorkian claims to have helped 35 people to die with the "mercitron" he invented, a jerry- built machine that allows patients to self-administer a fatal dose of drugs.

The courts granted Chip a temporary care order for his father, deeming that his mother was a danger to her husband. Later, however, a court in California ruled that Gerald could return to his wife on condition that even if euthanasia became legal there, he should not be subjected to it.

In Britain, the official view, as put by the BMA, is that there is no pain or suffering so great that it cannot be controlled with modern treatments, hence there should be no cause to end life prematurely. Doctors were scandalised by a recent episode of the television soap opera Brookside, which depicted a mercy-killing in which the daughter and son-in-law of a woman dying of cancer smothered her with a pillow to put her out of her misery after the GP had refused to prescribe more morphine for her pain. The BMA said there was no limit on the amount of morphine that could be prescribed and that no modern GP would behave in that way.

This is the crux of the matter. A doctor who prescribes steadily increasing doses of morphine to ease pain in the knowledge that this will shorten life is acting within the law, provided the intention is to relieve suffering. But if he says, as the Newcastle GP Dr Moor did at the weekend, that the intention was to end life, he has crossed a legal boundary and put himself at risk of arrest and prosecution.

The BMA believes that this legal distinction must be upheld in order to maintain the trust that patients have in their doctors. Otherwise, doctors may come to be seen as agents of death. Dr Vivienne Nathanson, head of science and ethics at the association, said: "Vulnerable people with a terminal illness should be able to turn to their doctor in trust without fearing that the doctor could put pressure on them to end their lives."

Others accuse the BMA of hypocrisy. A leading article in The Lancet last year said doctors' leaders were out of touch with the views of their members and were failing to recognise growing disquiet among the public over what happens at the end of life. It said: "There is a gap between what the profession collectively states and what individual members in practice sometimes do, under a cover that smacks of sophistry."

It dismissed the argument that euthanasia should be unnecessary with modern techniques of pain relief. "There will always be exceptions to the promise that no terminal state is so bad that it cannot be rendered, in a dignified way, pain-free." Even if there were no such exceptions, "some people may well feel that this route is not for them."

The BMA, which has more than 100,000 members, counter that at their annual meeting earlier this month doctors voted overwhelmingly to oppose moves to legalise euthanasia. "That is as representative as we can get," a spokesman said.

Signs of tension within the association emerged, however, when the meeting agreed by a narrow majority to include the words "for the time being", signalling their intention to return to the issue in the future.

Support among the public for euthanasia has been rising steadily. The latest British Social Attitudes survey, for 1996, indicated that 82 per cent of the public would back it in certain circumstances, up from 50 per cent in the early 1950s. Surveys of doctors show up to half are privately in favour.

They should be given pause by the findings of a small but instructive study carried out at Duke University in North Carolina, US. The study compared opinions among 168 frail elderly patients, average age 76, and 146 of their younger relatives. It found that the elderly who were most likely to be affected by euthanasia were least enthusiastic about it, 40 per cent being in favour compared with 60 per cent of their younger relatives. The poor and poorly educated who had the least power to influence policy were also the least happy about ceding to the state control over life and death