A bid to legalise assisted suicide will be launched in the Scottish Parliament today following the failure to clarify the law by a multiple sclerosis sufferer who has argued that her husband should be allowed to help end her life.

A bid to legalise assisted suicide will be launched in the Scottish Parliament today following the failure to clarify the law by a multiple sclerosis sufferer who has argued that her husband should be allowed to help end her life.

Debbie Purdy, who is a wheelchair user and is suffering from primary progressive MS, said the law had been left in a "confused mess" after the High Court in London rejected her attempt to elicit specific policy guidelines on the issue.

In a case which has been watched closely in Scotland, and split campaigners in favour of "mercy killings", Lord Justice Scott Baker and Mr Justice Aikens rejected Ms Purdy's application for judicial review on whether her husband will be prosecuted if he helps her travel abroad to die in a country where assisted suicide is legal.

However, they did allow her a right to appeal against the decision, in a move which could open up further lengthy court battles and ultimately end up in the European Court of Human Rights. While her case has been backed by campaign group Dignity in Dying, other proponents of voluntary euthanasia, including the Glasgow-based Friends at the End, expressed concern that it would backfire, placing greater pressure on prosecutors across the UK to bring charges against those who actively help their loved ones commit suicide.

In a parallel move, MSP Margo Macdonald, who has Parkinson's disease and previously said she should be allowed to bring about her own death if the condition deteriorates, will today outline her intention to issue a consultation regarding matters surrounding the choices she believes arise at the end of life. She hopes that this will lead to a Members Bill in the Scottish Parliament.

Dr Libby Wilson, a founder member of Friends at the End, said that while there had been numerous cases of Scots travelling abroad to end their own lives - some of them with the active assistance of the group - she was not aware of any prosecutions being instigated in the last decade.

She said: "I am concerned that, because of the publicity and attention that this case has brought, it will put the police, Crown and prosecution service under more pressure to be vigilant."

David Pannick, QC, argued on Ms Purdy's behalf that lack of proper guidance infringed her Article 8 right to private and family life under the European Convention on Human Rights.

He argued that Ms Purdy and her husband, Cuban violinist Omar Puente, were entitled to the guidance to enable them to "foresee" if Mr Puente was likely to be prosecuted if he helped his wife end her life.

However, the law lords ruled the Code of Practice for Crown Prosecutors in England and Wales already issued by the Director of Public Prosecutions, Sir Ken Macdonald, satisfied human rights convention standards and met the need for "clarity and foreseeability".