The High Court has lifted an injunction banning a man from taking his chronically-sick wife to Switzerland for an assisted suicide.
Assisted suicide is not illegal in some other countries
The woman, who has a progressive brain disease, is too ill to travel alone and would need someone to help her.
Family Division judge Mr Justice Hedley had issued a temporary injunction banning the trip.
But on Tuesday he said it was up to the police to decide what action, if any, to take against the husband.
The woman, known as Mrs Z, was diagnosed with cerebellar ataxia in 1997.
Her local authority, which provides care for her at home, had gone to court to clarify its role.
Mark Everall QC, representing the local authority, told Mr Justice Hedley that the husband was at first reluctant to help his wife end her life.
However, as her condition worsened, he started to make inquiries about the possibility of travelling to Switzerland, where there is no law preventing assisted suicide.
In the UK helping a person to commit suicide can result in a jail term of up to 14 years.
But the law on helping someone to travel to a country where they could receive help to end their life is unclear.
Mr Justice Hedley said Mrs Z was fully able to take her own decisions, and therefore it would be wrong for the court to intervene.
He said: "The court should not frustrate indirectly the rights of Mrs Z.
"The role of Mr Z is now a matter for the criminal justice agencies."
However, he stressed that in making arrangements to go to Switzerland Mr Z had "arguably committed an offence under Section 2 of the Suicide Act 1961."
He also ruled that the local authority had fulfilled its legal obligations by informing the police of the couple's plans to travel abroad.
Deborah Annetts, chief executive of the Voluntary Euthanasia Society, said the ruling had "far reaching" implications.
She said the fact that nobody had arrested the man, despite the fact that the law had probably been broken, was significant.
"I think people can take from this judgement that their right to self-determination is now pretty strong.
"It is becoming increasingly unlikely that the Director of Public Prosecutions will prosecute anybody who assists in such a case."
However, Ms Annetts said the law was a mess, and was in serious need of further clarification.
Phyllis Bowman, executive director of Right to Life, called the decision "outrageous" and said her group would be taking up the matter in parliament.
Anthony McCarthy, of the Linacre Centre for Healthcare Ethics, said: "We are talking about sanctity of life, which is fundamental to a just society, and an attempt to undermine that by a woman who is distressed by her condition."
Alistair MacDougall, chief executive of support group Ataxia UK, said: "I can understand how people can easily get to the point of despair and where they don't want to carry on.
HELPING PATIENTS DIE
Physician-assisted suicide:A doctor provides the patient with the means to end his or her own life, eg. by prescribing a lethal dose of medication for the patient to take at a time of his or her choosing.
Voluntary euthanasia: A person wishing to die is directly helped to do so by a doctor.
"People have been active, at the top of their careers. They often see their whole world crumbling, and they feel life isn't worth living."
Dr Vivienne Nathanson, of the British Medical Association, said most doctors had "overwhelming ethical, psychological and moral reasons" for opposing the idea of helping people to end their lives.
Non-profit organisation Dignitas runs a centre in Switzerland which has helped about 150 people end their lives.
Euthanasia is not illegal in Switzerland but the facility has become the centre of a row over "suicide tourists" travelling from countries where the practice is illegal.
The judge had asked for the case to be heard in public because it raised issues "that ought to be the subject of proper public discussion".
But he made orders banning identification of any of the parties, including the local authority involved and the local police force.