Kathryn, there is quite a difference between insisting that a doctor participate in an assisted suicide (unacceptable in my view), and what the British General Medical Council may be going to require. What they seem to be saying is that doctors cannot (under certain circumstances) refuse to withhold potentially life-prolonging treatment.
And what are those circumstances? That a desperately ill but compos mentis patient asks the doctor to withhold that treatment. A patient is fully entitled to ask for that, and a conscientious doctor has an obvious duty to comply or (as I would hope the GMC would allow) withdraw from the case.
My paternal grandfather was a physician, one of many doctors in my family. He was of the old school, born in the 1870s, and he had a very clear idea of the duty owed by a doctor to his patients. The doctor’s responsibility was to give the best possible advice to his patients. Note that word, “advice.” Apparently he always disliked the term “doctor’s orders,” which he felt was insulting to the patient. The doctor’s role was, he believed, to advise (and the advice could be given in very strong terms if necessary), but not command.
Of course, he lived in an era when more people believed that rational individuals could think for themselves.
In the age of the nanny state, such ideas are, of course, generally treated as heresy.