More than 100 Britons have travelled to Switzerland to make use of laws that allow assisted suicide, a practice prohibited in Britain.

The figure, released by Dignitas, the centre for assisted dying in Zurich, has been disclosed as a High Court test challenge begins today to the laws that ban aiding and abetting suicide.

Debbie Purdy, 45, from Bradford, who suffers from multiple sclerosis, says that the Director of Public Prosecutions (DPP) is obliged under human rights law to state when and in what circumstances he will prosecute people who help others to die.

Ms Purdy, a former marketing executive who uses a wheelchair and lives in a specially adapted home, wants to have the choice of ending her life if her illness becomes unbearable.

She wants to be able to travel to Switzerland to end her life, assisted by Dignitas, but accompanied by her husband, the Cuban jazz violinist Omar Puente. Under the present law he could face up to 14 years in prison for assisting a suicide.

Dignitas was founded in 1998 by Ludwig Minelli, a Swiss lawyer who runs it as a nonprofit organisation. It takes advantage of Switzerland’s liberal laws on assisted suicide, which suggest that a person can be prosecuted only if they are acting out of self-interest.

According to Dignitas the number of Britons among its assisted suicides reached 100 last month. There is, however, no independent verification of its figures.

Ms Purdy told The Times: “What I really want in an ideal world is not to have MS - or for anyone to have it - and for us all to live happily ever after.

But that’s not going to happen. So what I am seeking in the High Court is clarity - in what circumstances would they prosecute? If they say that my husband can collate the information, push me on to the train but not buy the ticket, then at least I know were I am.”

The clarification might help to determine when she would die, she said. “If I know I cannot be helped at all, then I might have to consider going earlier than I would otherwise do, when I am more able. But if my husband is able to help me with some of it, then I can delay - it may give me more time.”

But Ms Purdy, who used to enjoy an active life with outdoor pursuits that included parachuting, insisted that she had made no decision as to whether she would want to end her life. “I want the choice, the option. I don’t know if I will ever reach the stage when my symptoms are unbearable. So far, I have thought things would be unbearable - such as having to have a catheter - but it’s not. And I have a marvel-lous care team, as well as my husband, who says he will never let me get to that stage. But I can't be certain.”

Saimo Chahal, a partner with the London law firm Bindmans, who is acting for Ms Purdy, said that the case, which could go to the House of Lords, could result in a change in the law. “We are arguing that the right to life and the right to a private and family life under the European Convention on Human Rights should be interpreted broadly and should include decisions about the quality of life, including decisions about death if the quality of life is no longer good enough,” she said.

“On a practical level it is argued that the DPP should prepare a prosecution policy which tells the public what factors he will take into account when prosecuting in this area.

“It is only right that the public should know if they are likely to be charged with a criminal offence.”

Ms Purdy won leave in June to bring the High Court challenge, which is backed by the campaign group Dignity in Dying. Sarah Wootton, its chief executive, said: “We hope that common sense prevails and the judicial review will clarify the law so people considering travelling to Dignitas will know where they stand.”

The case is the first big challenge to the law on assisted suicide since that brought by Dianne Pretty, who died aged 43 in May 2002 from motor neuron disease. Her effort to change the law so that her husband could help her to end her life was rejected by the House of Lords in November 2001.

Final journey

— 3 areas outside Switzerland permit some form of assisted suicide: Belgium, the Netherlands and the state of Oregon in the United States

— 650 Britons are currently members of Dignitas

— 870 people have been helped to end their lives by the clinic

— 100 of them were from Britain

— 70% of those who request information about assisted suicide from Dignitas never contact it again

— 1941 when Switzerland made assisted suicide legal

Sources: Dignitas; Euthanasia Research and Guidance Organisation

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