The British Medical Association (BMA) has voted to re-instate its policy of outright opposition to euthanasia and doctor-assisted suicide, just a year after adopting a neutral stance on the issue.
The U-turn was greeted as a major victory for the campaign against euthanasia and follows similar votes this year by the Royal College of General Practitioners and the Royal College of Physicians.
Last month the House of Lords effectively rejected a bill brought by Lord Joffe that would have allowed terminally-ill patients to end their lives, with the assistance of a doctor, in very limited circumstances.
The campaign for a euthanasia law had been given a significant fillip when the BMA last year voted to move from clear opposition to such legislation to a policy of neutrality.
It was the first time in the association's 134 year history that it had dropped its policy against euthanasia.
But some doctors claimed that the vote had gone through with barely more than a third of the conference present and that the BMA's ethics committee was too biased in favour of a law.
At the conference yesterday, members voted 65 per cent in favour of a motion stating that physician-assisted suicide should not be made legal and by the same majority demanding that euthanasia should not be legalised.
Physician-assisted suicide involves a doctor giving the patients a means to commit suicide, such as prescribing a lethal dose of barbiturates that the patient then administers to themselves, whilst euthanasia involves the doctor themselves ending a patient's life.
Dr Peter Saunders, campaigns director of the Care Not Killing alliance that had galvanised support against a euthanasia law, said: "This debate showed that a clear majority of doctors are opposed to a change in the law.
"What we now have to do is to campaign to improve palliative care and educate the public to understand what such care can offer and that if a law came in, how vulnerable patients might feel under pressure to request an end to life."
Professor Ilora Finlay, a baroness who voted against the Joffe bill, said that 94 per cent of palliative care doctors were opposed to a change in the law.
She added: "Is it worse that someone lives days or weeks longer than they want to, or that someone ends their life days or weeks or even months earlier based on the wrong information?"
Prognosis cannot be certain and diagnostic errors are made.
"If patients are given the wrong information they may make the wrong decision."
Dr Andrew Davies, a senior house officer working on a cancer ward, told the conference that a change in the law would make many terminally ill people feel that they would have to make a request to die in order not to be a burden to relatives.
Dr Davies said: "My great concern is that a right to die will become a duty to die in order not to be a burden on their families.
"What these vulnerable people need is comprehensive palliative care provision, not laws, to respond to their demands."
But Dr John Fitton, a GP, backed a change in the law and said that people were being forced to travel to foreign clinics such as the Swiss organisation Dignitas in order to end their lives.
He said: "I know people still die in undignified misery.
"It is inhumane and disgraceful to have to be resourceful enough to travel to more enlightened countries for this service."
The Voluntary Euthanasia Society, which has recently changed its name to Dignity in Dying, has claimed that opinion polls show that a majority of the public is in favour of the legalisation of some form of assisted dying.
Deborah Annetts, chief executive of Dignity in Dying, said yesterday: "Today's vote in Belfast came amidst extensive lobbying by very active and organised religious lobby groups.
"A survey yesterday showed most doctors want neutrality, and resent a religious minority dictating policy across their profession.
"Millions of people in the UK will be deeply disappointed at what the religious lobby groups have done."