High Court judges have unanimously agreed that it would be wrong to depart from a precedent that equates voluntary euthanasia with murder. This means that a locked-in syndrome sufferer has lost a legal bid for the right to end his life of "pure torture".
Tony Nicklinson, 58, was left paralysed by a catastrophic stroke while on a business trip to Athens in 2005. He wept as the court ruling was announced on Thursday, saying he was "devastated" by the decision.
A second victim of the syndrome, referred to as "Martin", who cannot be identified, also lost his challenge to the ban on assisted dying.
Three judges sitting in London described their cases as "deeply moving and tragic", and their predicament as "terrible".
However the judges unanimously agreed that it would be wrong for the court to depart from the long-established legal position that "voluntary euthanasia is murder, however understandable the motives may be".
They ruled that the current law did not breach human rights and it was for Parliament, not the courts, to decide whether it should be changed.
In a statement issued by his lawyer, Nicklinson said: "I am devastated by the court's decision."
He continued: "I thought that if the court saw me as I am, utterly miserable with my life, powerless to do anything about it because of my disability then the judges would accept my reasoning that I do not want to carry on and should be able to have a dignified death.
"I am saddened that the law wants to condemn me to a life of increasing indignity and misery."
The patient known as "Martin" also released a statement through his lawyer, saying he felt "even more angry and frustrated" following the judgment.
"My life following my stroke is undignified, distressing and intolerable," he said.
"I wish to be able to exercise the freedom which everyone else would have - to decide how to end this constant tortuous situation."
Nicklinson's wife Jane, standing by her tearful husband at their home in Melksham, Wiltshire, described the decision as "one-sided". "You can see from Tony's reaction he's absolutely heartbroken," she said.
She said they would now appeal the decision and hoped they would be able to organise a hearing before the end of the year.
Asked what would happen if the appeal fails, she said: "Tony either has to carry on like this until he dies from natural causes or by starving himself."
Both Nicklinson and Martin are victims of locked-in syndrome. They suffer from catastrophic physical disabilities, but their mental processes are unimpaired and they are fully conscious of their predicament.
Barring unforeseen medical advances, neither man's condition is capable of physical improvement.