Leslie Burke suffers from the degenerative brain disease cerebellar ataxia, a condition which means he has such poor balance he has to use a wheelchair. His co-ordination and speech are also impaired.
But, however bad his illness becomes, the 44-year-old's mental faculties will not be affected.
Mr Burke took his case to the High Court in a bid to change General Medical Council guidelines which currently allow doctors to choose whether he should be kept alive if his conditions worsens dramatically.
It is thought to be the first 'right-to-life' case of its kind.
Mr Burke, of Mardale Road on Newton Estate, feared that if his condition deteriorated doctors could decide that his quality of life was so poor that he should not be kept alive.
But on Friday the High Court ruled that doctors must base their decisions on their patient's wishes.
Judge Mr Justice Munby said Mr Burke's wishes should be respected.
"I feel ecstatic," Mr Burke said. "I had no idea which way the judgment would go. I am just so pleased about it. It just seems like a great weight lifted off my shoulders.
"The right to die with dignity is very important to me."
After the judgment, Bert Massie, chairman of the Disability Rights Commission, said: "This judgment provides genuine protection for disabled people with serious long-term conditions.
"They want health professionals to do as much as possible to preserve life – as they would do for non-disabled people."
Neurological experts say Mr Burke could live another 15 to 20 years.
The former postman was first struck down with the illness in his teens, and it was diagnosed when he was 23.
His 43-year-old brother Robert has the same condition at a more advanced stage.
Lawyers had argued during the three-day High Court hearing held in February before Mr Justice Munby that patients like Mr Burke should be given food and water until they die naturally. They said the GMC's guidance on life or death decision-making contravenes his rights under the Human Rights Act.
Barrister Richard Gordon QC said: "Patients like Mr Burke may die when they don't want to die. They may die because of the withdrawal of artificial nourishment and hydration by clinicians who think it is in their best interests. Some patients might make a different choice, but Mr Burke states quite clearly that he wants to continue to be fed until he eventually dies of natural causes."
But the GMC had argued that there was no evidence that doctors would refuse to keep him alive, and Mr Burke's legal team had merely entered into an attempt to 'proffer answers to hypothetical questions of law'.