Euthanasia is extremely rare in the UK and few doctors want to see it legalised, a study says.
The late Diane Pretty fought a long court battle for an assisted death
Pro-euthanasia campaigners have long argued terminally-ill patients are helped to die in secret.
But fewer than 1% of deaths were by euthanasia in 2004 and few doctors want to see the law change, the Brunel University survey of 857 doctors found.
Euthanasia and doctor-assisted suicide, whereby the patient is given the means to kill themselves, are both illegal.
Of the 584,791 deaths in the UK in 2004, 0.16% (936) were by voluntary euthanasia, the survey revealed.
Some 0.33% (1,930) involved the doctor ending a patient's life without consent from the patients, for instance if they are in a coma. This is sometimes known as involuntary euthanasia.
But not one GP or hospital doctor said they had taken part in physician-assisted suicide in the poll which asked them to report on the last death they had attended.
A third of deaths were put down to alleviating symptoms which may have the effect of shortening life, while just under a third were from withholding treatment because it is deemed in the best interests of the patients. Both practices are legal in the UK.
Just 2.6% of doctors said changing the law would benefit patients.
It is the first time such a comprehensive study into medical practice has been undertaken in the UK and shows euthanasia rates are lower than in many other countries.
Report author Professor Clive Seale said: "Euthanasia and physician-assisted suicide are understandably very emotive subjects, but this work shows that UK doctors are less willing to take such actions than in several other countries.
"We have a very strong ethos of providing excellent palliative care in the UK, reflected in the finding that doctors in the UK are willing to make other kinds of decisions that prioritise the comfort of patients, without striving to preserve life at the cost of suffering.
"The results suggest that providing the best kind of patient care is a major driver behind medical decision making."
The findings come after a private members bill was introduced into the House of Lords in November proposing a relaxation of laws governing doctor-assisted dying.
Lord Joffe's bill advocates assisted dying, whereby doctors can prescribe a lethal dose of medication for a patient to take themselves.
But proposals to legalise voluntary euthanasia, where the doctor actually helps a patient die, which were in his original draft, were dropped.
Deborah Annetts, chief executive of the Voluntary Euthanasia Society, said the report supported the calls for a change in the law.
"This research proves some doctors break the law and deliberately help patients die.
"This is all done in secret and denied in public. This cannot be safe."
But Julia Millington, political director of the ProLife Alliance, said: "Surely the response of a civilised society is to stop this unlawful killing altogether rather than use such research to support demands for doctors to be permitted to do it legally."
And Dr Vivienne Nathanson, head of science and ethics at the British Medical Association, said she was "concerned a tiny minority of doctors have apparently admitted they have acted illegally in deliberately ending a patient's life".