A patient has won his legal challenge to prevent doctors withdrawing life-prolonging treatment.
Les Burke fears he will starve to death unable to communicate
Leslie Burke, who has a degenerative brain condition, feared doctors could withdraw food and drink against his wishes when he can no longer speak.
He was concerned existing General Medical Council guidance on giving artificial nutrition could allow his wishes to be over-ruled.
The High Court ruling means that guidance will now have to be redrafted.
The ruling will affect patients who are terminally ill and those with a disability who are unable to communicate their wishes about their treatment.
However, the GMC has said it is considering an appeal.
After the ruling, Mr Burke, 44, from Lancaster, who has cerebellar ataxia, told BBC News Online: "There have been times when I have found this quite painful, especially emotionally but it has all been worthwhile.
"I am quite happy at the moment as you can imagine."
Mr Burke, who is in a wheelchair, added: "The onus should be on helping people to live, not despatching people too early.
"The patient should have the last say."
He said he would not want feeding to be withheld, "even if it's only a matter of an extra couple of days, or a couple of weeks".
The GMC guidance covers situations where death is not imminent, but doctors believe a patient's condition is so severe, and their prognosis so poor, that artificial nutrition or hydration - giving water - causes more suffering than benefit.
It says that if patients are no longer able to communicate their views, doctors must judge what the patient would want, based on earlier discussions or written statements, and in consultation with patient's relatives.
But Mr Burke had argued that doctors may make a subjective judgement that the patient's quality of life was lower than another person's.
He argued the guidance should be changed so that doctors will have to presume a patient wants to carry on living.
Judge Mr Justice Munby said of the guidance: "The emphasis throughout ... is on the right of the competent patient to refuse treatment rather than on his right to require treatment.
"One can see the error creeping into the guidance in different ways."
He said he took issue, in a number of respects, with what the guidance said about the law.
He added: "It follows, in my judgment, that the claimant has in principle established his right to relief."
That relief is expected to take the form of agreed declarations of a patient's wishes.
Liz Sayce of the Disability Rights Commission said it was a "great victory" for Mr Burke and other people with long-term conditions.
"Many people have been afraid that their own wishes to carry on having treatment could be over-ruled."
Ms Sayce added: "If someone is not disabled themselves, they can assume that a patient's quality of life looks really terrible, and it could be better to let them go.
"But the person might not think that at all."
She added: "This ruling puts the power back where it belongs - with the person with the condition."
In a statement, the GMC said: "We are glad that Justice Munby confirms, as we have said, that Mr Burke is entitled to have his wishes followed.
"As the case raises important points of principle, and there are some areas where we consider further clarification may be needed, we have sought leave to appeal."
It added that the judgement clarified "a number of important areas", including making it clear that doctors are not obliged to provide treatment that is futile, or places an intolerable burden on the patient.
"It is our stated position that in cases where there is disagreement over the care of a patient, the courts should be approached for a ruling."
Dr Michael Wilks, chair of the British Medical Association's medical ethics committee, said: "A decision to withhold or withdraw treatment from a patient who is dying or seriously ill is one of the most difficult and complex decisions a doctor can make.
"It is therefore absolutely essential for patients and their families, as well as for the health professionals providing care, that guidance be as clear as possible."