A woman suffering from multiple sclerosis has gone before the House of Lords for a ruling that would save her husband from prosecution if he accompanies her life to the controversial Swiss clinic Dignitas.
She is telling the Lords that she will be forced to end her life earlier than planned if laws banning assisted suicide are not changed.
In England and Wales, aiding and abetting suicide is a criminal offence punishable by up to 14 years in jail.
Ms. Debbie Purdy, 46, is losing strength in her upper body and plans to travel to Switzerland to end her life if her condition becomes unbearable.
Lord Pannick QC, representing Ms Purdy, said: "She will not be able to make the arrangements without the assistance of her husband who will consequently be at risk of prosecution.
"If the risk of prosecution is sufficiently low, she can wait until the very last minute before travelling with her husband's assistance."
He said if the risk was high, she would have to go earlier while she was still fit enough to travel without assistance.
He added, "It is ironic that the policy designed to protect the sanctity of life will have the effect of shortening the life of terminally-ill persons such as Ms Purdy.
"She would also not have the comfort of having her husband with her at the end of her life."
She has taken her case to the High Court and the Court of Appeal but failed to secure a definitive ruling that her husband, Omar Puente, would not face prosecution if he travelled with her.
Ms Purdy's lawyers had argued that the Director of Public Prosecution's failure to make it clear whether her husband would be prosecuted was a breach of her right under the European Convention to respect for private and family life. That didn't find any takers in the judiciary.
But, in their ruling, Lord Justice Scott Baker and Mr Justice Aikens of the Court of Appeal, gave her the right to appeal and said helping a loved one to go abroad to end their suffering was something "many would regard that the law should permit."
They also noted: "We cannot leave this case without expressing sympathy for Ms Purdy."
The judges' comments were seen as a strong indication that Parliament should review legislation drawn up in the 1961 Suicide Act.
Speaking before the case alongside her husband, Ms.Purdy said she was "excited and hopeful" and was seeking only to "clarify" existing law rather than change it.
Campaign group Dignity in Dying warned on Monday that there were 34 Britons in the final stages of preparing for an assisted death abroad, in a new report.
In February, research by GP magazine found that almost 40 per cent of doctors wanted euthanasia to be legalised.
Sir Ken Macdonald, a former DPP, said it was time to consider reforms. The law on assisted suicide should be reformed and is "lagging behind" the British public's beliefs, he said.
Ms Purdy's case is being opposed by the current DPP Keir Starmer QC, who argues that the general code of practice is sufficient and he should not be required to issue specific policy guidelines.
He has refrained from prosecuting in around 100 cases where family members have helped terminally ill patients travel to Switzerland to end their lives, he points out.