Many people who heard Debbie Purdy’s dignified plea for clarity on whether her husband would be prosecuted if he assisted her suicide have been moved by the reasonableness of her request. Lord Justice Scott Baker said the court could not leave the case without expressing “great sympathy”.

Yet the judges said that they will not change the law. Standing in the way of Ms Purdy’s request is the Suicide Act 1961, which states that any person who “aids, abets, counsels or procures the suicide of another” could be liable for a prison sentence of up to 14 years. Lord Justice Scott Baker said that only Parliament could change the law.

That is not strictly true. The common law as expounded by judges can be used to interpret, for instance, what is meant by a word like “aids”. And it could compel the state prosecution service to give citizens clear guidance on what the law means.

The law is everybody’s law and it should never be opaque. As it is, the law on suicide is a stale mess. There is a compelling case for it to be redesigned to meet the sensible expectations of reasonable, law-abiding citizens such as Ms Purdy. No patient should have to suffer immeasurable pain against their will just to salve the morality of others who think there is a purpose in such agony.

Certainly, there is a serious issue at the core of the legal debate: the conflict between the need for society to have rigorous rules against all forms of homicide and the right of an individual to determine their own fate. Yet the law as it stands is based on an old-fashioned view of suicide.

Some people talk about suicide as a sin. That is nonsensical. (How could any rational person listening to Debbie Purdy regard her as morally derelict?) In fact, the classification of suicide as a sin is not biblical — it was invented by St Augustine of Hippo (345-430 AD) for pragmatic reasons. Some early Christians chose to end their lives immediately after baptism, believing it was a way of avoiding sin and going to heaven. To prevent an impending decimation of believers, St Augustine taught that suicide was a sin worse than any likely to be committed by those who chose to stay alive. Eventually, English law stigmatised it as a criminal act, forbidding suicides a Christian burial, confiscating their properties and often pauperising their families.

It is time the law evolved once again. Ms Purdy can only hope that the appeal courts will be less inclined to sit on the fence or that Parliament will act promptly to make a new law.

Professor Gary Slapper is the Director of the Centre for Law at the Open University. He writes a weekly column for Times Online, The Law Explored, elucidating the complexities of British law.

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