The House of Lords has twice recently been asked to give its opinion on this most difficult and morally perplexing matter. It did so in the context of its roles both as a legislative body and as a Court. It is perhaps a reflection of the anguished complexity of the subject that it gave two apparently contradictory responses.

On the one hand, Debbie Purdy won her appeal last week, requiring Keir Starmer, the Director of Public Prosecutions (DPP) to give clearer guidance as to how discretion might be exercised in considering prosecution of her husband for aiding and abetting her suicide abroad, contrary to the Suicide Act. In the same breath (quite literally referred to in Baroness Hale's Judgement "As I begin to write this opinion...") the House last month rejected a proposed amendment to the Coroners and Justice Bill which would have enabled people to assist someone with a terminal illness in travelling to a country where assisted suicide is legal.

Mrs Purdy has multiple sclerosis and is inexorably deteriorating. She believes that she will probably come to a point when she no longer wishes to live and so will travel abroad, probably to Switzerland, to die. The problem is, that she will not be able to do this alone. She will need help from her husband and is understandably anxious that he may be prosecuted for aiding and abetting her death.

Unlike the equally high-profile case of Mrs Pretty in 2002, Mrs Purdy was not asking for a guarantee of immunity from prosecution. Instead, all she asked was that the Court look at the DPP guidelines on exercising its discretion on prosecution and see if they were adequate. The House of Lords did so and found they were not.

There is no doubt that if he did enable Mrs Purdy to die in Switzerland, her husband would fall squarely into the offence under s 2(1) of the Suicide Act 1961. There is, however, a significant difference between falling within the technical definition of an offence and a decision to prosecute. That lies with the discretion of the DPP and it was this discretion that Mrs Purdy sought to challenge – what guidance could she seek that would inform her decision? The House of Lords found that the DPP's guidance failed to give the necessary accessibility to the public and also failed to provide reassurance that the law will not be interpreted arbitrarily.

The DPP stoically argued that it was impossible to give any more detailed guidance as each case was so individual. He argued that if any more specific guidance was to be given, it would restrict the scope of the discretion necessary for the Director. The House of Lords listened to these arguments patiently and sympathetically but subsequently dismissed them. Lord Hope, delivering the most detailed opinion, accepted the cases were few (though increasing) and sensitive to individual facts. Never the less, he thought this could not excuse the DPP's failure to provide guidance to the public to assist them in making a decision.

All of the Lords were emphatic that they were not supporting Mrs Purdy's right to travel abroad and end her life. With equal emphasis, they confirmed that they were not seeking to legalise 'assisted dying'. They were simply requiring the DPP to provide clearer guidance as to how discretion in such cases would be exercised in the future. The DPP is due to publish interim clarification next month.

In one sense, this is a step forward for those campaigning for the ultimate aim of enabling patients, such as Mrs Purdy, to die with dignity at a time, and in a manner, of their own choosing. In another sense, the House of Lords defeat of a proposed amendment to the law prohibiting aiding and abetting suicide shows how deeply concerned many remain about such a change of attitude. The proponents of the 'right to die' may soon be reassured that they will probably not face criminal prosecution for their actions, but are a long way off from a fully legalised process to legitimise the 'right to die'.

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