Multiple sclerosis sufferer Debbie Purdy has taken her fight to allow her husband to help her commit suicide to the House of Lords.
A panel of five Law Lords was told that if the UK law banning assisted suicide was not changed, she may be forced to end her life earlier than she planned.
And if she had to go to Switzerland, where assisted suicide is lawful, on her own, then her husband would not be there to comfort her at the end.
Ms Purdy has so far failed to secure a definitive court ruling that her husband, Cuban violinist Omar Puente, would not face prosecution if he helped her travel abroad to die.
Under English law, aiding and abetting suicide is a criminal offence punishable by up to 14 years imprisonment.
Lord Pannick QC, representing her, told the Law Lords, headed by the former Lord Chief Justice Lord Phillips, that Ms Purdy, 46, was diagnosed with multiple sclerosis in 1995.
"She accepts there will come a time when her continuing existence will become unbearable for her, at which point she will wish to end her own life."
But he said that by that time she will be incapable of taking her own life without help and this would mean travelling abroad to a country where assisted suicide is legal.
"She will not be able to make the arrangements without the assistance of her husband who will consequently be at risk of prosecution.
"This places them in what the Court of Appeal described as an impossible dilemma."
