The woman, 65, known as Mrs Z, is understood to have been accompanied to Zurich by her husband to whom she was married for 45 years.

The death of the woman, whose identity is the subject of a court injunction, came on Wednesday after a hearing before Mr Justice Hedley on Tuesday.

The judge lifted a ban on her husband, 66, a former insurance clerk, taking her abroad in the first case of its kind. He stopped short of sanctioning what has been called “suicide tourism” after a number of cases in which people travelled abroad to die.

Instead he left the decision to the police and the Crown Prosecution Service to determine if any action should be taken against the husband.

Assisting a person to commit suicide in Britain is punishable by up to 14 years in jail, but police are unclear whether helping someone to travel to a country where it is legal constitutes aiding a suicide.

The test case was brought by a local authority which learnt that the couple, from Cheshire, were preparing to go abroad.

Mr Justice Hedley ruled that the couple, who are believed to have had three children who reluctantly accepted their mother’s wishes, should not be identified.

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.”

A spokesman for the Voluntary Euthanasia Society said it had had no direct involvement in the case and had not received confirmation of Mrs Z’s death.

But the spokesman added: “This is a very important judgment, a watershed. It means that the Suicide Act is on its last legs. It raises all kinds of public policy issues.”

Giving judgment after a day-long hearing, the judge said that Mrs Z suffered from cerebellar ataxia, an incurable degenerative brain disease that would ultimately affect all organs and lead to her death.

Her local authority had known that she wished to commit suicide.

At least 22 Britons have been helped to commit suicide by a Swiss clinic run by the non-profit organisation Dignitas.

• A hospital in the Nether lands, the first country to legalise euthanasia, has started to kill terminally ill and severely disabled babies with the consent of their parents.

  The Groningen Academic hospital disclosed that it had begun to carry out involuntary euthanasia, including administering lethal doses of sedatives to newborn babies in a procedure known as post-birth abortion.

  The hospital said that it had drawn up guidelines on involuntary euthanasia and carried out four such mercy killings of babies last year. The cases were reported to government prosecutors, but no legal proceedings were started.

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