A woman with multiple sclerosis has failed in a bid to force the director of public prosecutions for England and Wales to issue guidance clarifying whether her husband would face prosecution if he helped her travel to Switzerland for an assisted suicide.

Two senior judges at the High Court in London acknowledged that many people would regard such help as “something that the law should permit” but said that only parliament could change the law.

Debbie Purdy, 45, wanted Ken Macdonald, the director of public prosecutions, to outline the circumstances in which a helper might risk prosecution for aiding or abetting suicide in a country where assisted suicide is lawful. Assisting a suicide …