Who would have thought that doctors could be so squeamish about death? It happens to all of us and those professionals running intensive care units see a lot more of it than most. Yet the doctors caring for Miss B, the quadriplegic woman at the centre of the right-to-die case which has transfixed the nation, are adamant that they will not be the ones to switch her ventilator off.

Few who witnessed it - whether at her bedside or relayed to a video screen in a courtroom - will forget the dramatic moment when the 43-year-old former senior social worker starkly told Dame Elizabeth Butler-Sloss, England's senior family judge, sitting at the foot of her bed: "I want to be able to die."

Within the next few weeks, the chances are that she will get her wish. English law is perfectly clear, as Dame Elizabeth pointed out herself in an earlier judgment: "A man or woman of full age and sound understanding may choose to reject medical advice and medical or surgical treatment either partially or in its entirety. A decision to refuse medical treatment by a patient capable of making the decision does not have to be sensible, rational or well-considered."

Or, as the law lords put it in the case of Tony Bland, the landmark right-to-die case nearly 10 years ago: "If an adult patient of sound mind refuses, however unreasonably, to consent to treatment or care by which his life would or might be prolonged, the doctors responsible for his care must give effect to his wishes, even though they do not consider it to be in his best interests to do so."

That's just what the doctors responsible for Miss B's care have not been prepared to do. They have maintained their stance for the year or so that she has been demanding the right to dispense with the technology keeping her alive against her will.

Nor have they managed to locate another medical team willing to carry out her wishes, forcing Miss B to risk her life savings taking them to court. (The NHS trust has since agreed to pay her legal costs.) "I was told over and over again that no doctor would ever do this," she told the court. "Yet, through my own network of friends, I was able to identify several doctors who disagree with that point of view."

It was left to Miss B, confined to a hospital bed and paralysed from the neck down, to find the eminent director of an intensive care unit at a leading hospital who has now agreed to do what she wants, if the high court rules she is mentally competent to take the decision. He has never switched off a ventilator in similar circumstances but said in his report to the court: "I believe her wishes deserve respect."

Another similar, but older, patient in his unit who wants to stay on the ventilator at present has been told that "should he change his mind at any time in the future, we will certainly be prepared to switch the ventilator off."

There is little doubt that Dame Elizabeth will declare Miss B perfectly capable to decide for herself. Indeed, since last August, when she was assessed by an independent psychiatrist who pronounced her competent, doctors have treated her as a patient able to take her own decisions - though still resisting her pleas to switch off the ventilator. The official solicitor, acting as an independent adviser to the court, has concluded on another psychiatrist's advice that she is competent to decide.

Miss B views her current plight as worse than death. Doctors want her to try rehabilitation before she makes an irrevocable decision. But she has fully explored that option and knows it will not improve her physical condition. A portable ventilator would enable her to get around in an electric wheelchair, but she would still not be able to manage her own personal care. She is washed and her bowels are evacuated by nursing staff as she lies on her bed, processes she regards as humiliating. Single and childless, she does not want the most intimate of functions performed for her by paid care staff. She has frequent muscle spasms and never feels really comfortable.

But she has been heartened by having her voice heard by the court, says her solicitor, Richard Stein, of London law firm Leigh, Day & Co. "Even before judgment, she feels the proceedings have already made a lot of difference. Whereas before she felt very much on her own, it's now clear that there's a general consensus in the country that she's got a right to make decisions about her future."

Though Miss B is the first patient in the UK to go to court to have a ventilator switched off, this is not the first time the high court has grappled with the issue. In a case in August 2000 which escaped the media's notice, Mr Justice Hughes said doctors did not need a court declaration to switch off the ventilator keeping a 19-year-old man with motor neurone disease alive, at the patient's request. Unlike Miss B, he had a terminal illness. But the judge's pronouncement applies equally to her case: "The continuation of invasive ventilation, if it is clearly established that an adult patient of full capacity has withdrawn his consent to it, is not simply not the duty of the doctor but is positively unlawful."

Miss B's doctors told the court they were unwilling to turn off the ventilator because they would be killing their patient. Not so; as Lord Goff said in the Bland case: "The doctor, in discontinuing life support, is simply allowing his patient to die of his pre-existing condition."

No one, least of all Miss B, imagines that the doctor who pulls the plug will be emotionally unmoved. Miles Edwards and Susan Tolle, two American doctors who disconnected a paralysed man from a ventilator at his request, wrote about the experience in the Annals of Internal Medicine 10 years ago.

The 67-year-old man with post-polio syndrome was surrounded by his family, holding his daughter's hand. "A heavy feeling of intense emotion consumed both of us as we slowly injected midazolam (a sedative) and morphine, watching the patient closely so we could produce the desired level of drowsiness," the doctors wrote.

"Within a minute or so, the patient turned slightly cyanotic [blue] and began to struggle. With trembling hands we pushed more midazolam and morphine. Mr Larson (not his real name) seemed comfortable. He exchanged smiles with his daughter. He appeared reasonably comfortable and relaxed. We both felt a great heaviness and deep sense of anxiety.

"Mr Larson did not struggle further. About 30 minutes passed, although it seemed like hours. The patient then gradually slipped into a coma. Fifty-three minutes after he was disconnected from the ventilator, we pronounced him dead.

"Although we received grateful hugs from the family and thanks from the health care team, we were struck by the gravity of what we had done. Doubts kept creeping into our minds. We each experienced a wave of disquieting emotion, feelings that we had killed this patient who would otherwise have continued to live connected to the ventilator. We knew intellectually that he had the legal and ethical right to refuse this medical treatment, but the gravity of his decision and our participation haunted us.

"We've seen our patients die of their various diseases, but now our acquiescence in allowing his death caused us much anguish. One of us sought counsel from a psychiatrist who reinforced our belief that we did the right thing, counteracting those deep feelings that somehow we had killed this patient. Gradually we came to terms with what had happened. Our consciences were clear, but we were left feeling very impressed with how difficult it had been to honour this man's request."

A decade later, the memory is still vivid for Tolle, director of the centre for ethics in health care at Oregon Health & Sciences University. "I was very touched by how successful we were in securing his comfort and having him awake enough to mouth 'I love you' to his daughter. It was a terribly touching moment. I'll never forget it. He was able to really be present till the last minute. The moment he struggled was just 10 seconds. We quickly reconnected him and gave him more medication. It was because we had so little to guide us."

It was Edwards who went for counselling, she reveals. "He has strong pro-life beliefs. So for him to do this was a very big, very important issue, showing how he feels about the burdens of medical treatment and choice versus things like abortion, the death penalty and physician-assisted suicide, all of which he believes are morally wrong. But he believes it's the right of an individual to refuse life-sustaining treatment and allow life to follow its natural course."

Tolle believes patients such as Miss B, previously healthy but suddenly quadriplegic, need time and full information to make up their minds whether they can or cannot live with their disabilities. "I think she has a right to say 'I don't choose it. It is not for me, I have lived it. How many ways do I have to tell you now?'

"Ethically, starting treatment and stopping it should be no different. If we don't support that kind of philosophy, that treatments do not become obligatory because you started them, then people will refuse things they might otherwise choose for fear they'll be stuck on them. We carry a very heavy burden if we make you choose in advance and we give out one-way tickets for medical treatments."