A High Court judge has ruled that it is in the best interests of a woman who suffers from "extremely severe" anorexia to be fed against her wishes.
Mr Justice Peter Jackson found that the 32-year-old, who has other chronic health conditions, "lacked capacity" to make a decision about life-sustaining treatment.
Sitting at the Court of Protection in London, the judge said it was a "very difficult decision" to make in a situation requiring "a balance to be struck between the weight objectively to be given to life on one hand and to personal independence on the other".
Her case had "raised for the first time in my experience the real possibility of life-sustaining treatment not being in the best interests of a person who, while lacking capacity, is fully aware of her situation".
Giving his conclusion in a judgment made public today, he said: "The competing factors are, in my judgment, almost exactly in equilibrium, but having considered them as carefully as I am able, I find that the balance tips slowly but unmistakably in the direction of life-preserving treatment.
"In the end, the presumption in favour of the preservation of life is not displaced."
He declared that "it is lawful and in her best interests for her to be fed, forcibly if necessary".
The "resulting interference" with the rights of the woman, who lives in Wales and cannot be named for legal reasons, but is referred to as E, was "proportionate and necessary in order to protect her right to life".
The judge said of her: "Albeit gravely unwell, she is not incurable. She does not seek death, but above all she does not want to eat or to be fed.
"She sees her life as pointless and wants to be allowed to make her own choices, realising that refusal to eat must lead to her death."
Her case came before the court last month when an urgent application was made by her local authority, which also cannot be identified, which was "concerned that her position should be investigated and protected".
Mr Justice Jackson said: "E's death was imminent. She was refusing to eat and was taking only a small amount of water.
"She was being looked after in a community hospital under a palliative care regime whose purpose was to allow her to die in comfort."
The former medical student, described as an "intelligent and charming person", who began to control her eating at the age of 11, has not taken solid food for more than a year and when her Body Mass Index (BMI) was last measured it was 11.3 - a healthy BMI is in the region of 20.
E, who has also abused alcohol since adolescence as a "means of escape", has an "obsessive fear of weight gain". She was "an adult with an entrenched history of acute difficulties".
The judge said: "For E, the compulsion to prevent calories entering her system has become the card that trumps all others. The need not to gain weight overpowers all other thoughts."
Explaining the reasons for his decision, the judge said: "At its simplest, the balance to be struck places the value of E's life in one scale and the value of her personal independence in the other, with these transcendent factors being weighed in the light of the reality of her actual situation."
He said: "In E's situation, any decision is a heavy one. The balancing exercise is not mechanistic, but intuitive, and there are weighty factors on each side of the scales.
"On one side, I have been struck by the fact that the people who know E best do not favour further treatment.
"They think that she has had enough and believe that her wishes should be respected. They believe she should be allowed a dignified death."
He said he acknowledged the "impossible" position of her parents and had also reflected on what was involved in the course of treatment.
"It does not merely entail bodily intrusion of the most intimate kind, but the overbearing of E's will in a way that she experiences as abusive."
The judge also said E's views "are entitled to high respect".
He added: "She is not a child or a very young adult, but an intelligent and articulate woman, and the weight to be given to her view of life is correspondingly greater."
Regard "must also be had to the fact that this application was only brought after E and her family and carers had embarked a long way down the course of palliative treatment".
He added: "The state is now seeking to intervene very late in the day and a return to compulsion will be excruciating for them."
The judge said he acknowledged the significant risks involved in treatment, "not excepting a risk to life", the modest prospects of success, the "wholesale and prolonged invasion of E's privacy and self-determination that is proposed", the "high chance that, even if short-term progress can be made, long-term difficulties will remain" and accepted that a resumption of treatment "deprives E of an imminent and relatively peaceful death".
Against those "weighty factors", the judge said he placed E's life "in the other scale".
He said: "We only live once - we are born once and we die once - and the difference between life and death is the biggest difference we know.
"E is a special person, whose life is of value. She does not see it that way now, but she may in future."
The judge went on: "I would not overrule her wishes if further treatment was futile, but it is not. Although extremely burdensome to E, there is a possibility that it will succeed.
"Services and funding will now be provided that were not available before and it would not be right to turn down the final chance of helping this very vulnerable young woman."
He said he was also influenced by the fact that those who know her best were not in outright opposition to treatment taking place, "however sceptical they justifiably feel".
The judge said: "I record that the state, having instigated this plan of action for E in the way that it has, is now honour-bound to see it through by the provision of resources in the short, medium and long-term.
"Had the authorities not made that commitment, I would not have reached the conclusion that I have."