Whose Life Is It Anyway? asked Brian Clark 30 years ago. Yesterday came a tentative answer. Clark's play told of a sculptor paralysed from the neck down in a car accident who wanted to be allowed to die. But the hospital he was confined in held it a duty - not to mention a legal imperative - to preserve his life at all costs.

The guidelines on assisted suicide just published - in London by the Director of Public Prosecutions, separately here by the Public Prosecution Service - don't deal directly with the circumstances set out in Whose Life..?. But they move the debate significantly closer to the core issue which Clark dramatised.

I saw the play in London's Mermaid Theatre on its initial run, Tom Conti in the lead. The production deservedly won the 1978 Olivier Award, then a Tony on Broadway the following year. What made it palpitate in the emotional mind long afterwards was that Clark presented the man who wished for death not as a demented wretch wracked by intolerable pain, but as a witty, bright, vibrant person trapped in a bone-house prison, who just wanted release.

The deaths of Sir Edward (85) and Joan Downes (74) in July brought the play back to mind. The couple had been devoted to one another through 54 years of marriage. He was widely regarded as one of the 20th century's finest interpreters of Verdi and Wagner, had conducted every year at the Royal Opera from 1952 to his last Rigoletto in 2005. Joan was a dancer, a choreographer and latterly her husband's assistant and then carer.

Just a few years ago, Sir Edward's sight began to fade. Eventually, unable to read the score, he had to abandon new music and conduct from memory. Then his hearing went. For a time, Joan guided his stumbles in the unseen silent world which he had filled with sound and light for half a century. Last year she was diagnosed with terminal cancer. In July, the pair travelled to the Dignatas clinic in Zurich which they entered hand in hand to die in peace together.

The Metropolitan Police, as was required, launched an investigation into whether they had had help to travel abroad.

Jo Cartwright of the campaign group Dignity in Dying commented: "The case illustrates the need for a change in the law. We need to regulate and safeguard (assisted suicide) in this country, to make it available only to those who are terminally ill and mentally competent. Going abroad is a terrible strain - and not cheap." (Costs at Dignitas average £3,500).

A fortnight earlier, the House of Lords had voted down a measure introduced by former Lord Chancellor Lord Falconer which would have obviated the need to travel abroad by making it lawful to help a terminally ill person die in the UK. A letter appealing to peers to reject the move was signed by Dr Vincent Nichols, Catholic Archbishop of Westminster, Dr Rowan Williams, Anglican Archbishop of Canterbury, and the Chief Rabbi, Sir Jonathan Sacks. Islam takes a similar view.

The rejection of Falconer's amendment gives sharper significance to the guidelines announced yesterday. The new initiative was prompted by the decision of the law lords, also in July, that Bradford woman, Debbie Purdy, had a right to know whether her husband would be prosecuted if he helped her travel abroad to die. Ms Purdy, 46, has multiple sclerosis. The law lords, in effect, ordered the prosecution authorities to spell out the legal position so she could make an informed choice.

Here and across the water, the guidelines are to be put out to consultation. One focus of debate will concern whether the rules on travelling abroad should also provide a framework for the operation of law at home - the system which Falconer had tried to put into law. In effect, will the act of assisting in the suicide of a terminally- ill person be decriminalised?

We can expect determined efforts to ensure that, irrespective of what happens in England and Wales, no such interpretation is allowed in the North.

Opportunities will arise for a re-run of the wrangle over the extension of the Abortion Act - involving opportunities for local MPs to explain to admiring pro-lifers in London that life is held more precious here than in less godly regions.

What's still in dispute, even after all these years, is Whose Life is it Anyway?

God's? And therefore God's alone to take away? Always assuming, as assumption is all it can be, that there's such a thing as God.

Or do we have a right to call on those we love and who love us in return to give us ease and assist at its ebbing away?

Will we see again our four main parties lined up with their allies from the last set-to, the orange and green warriors from the stained battlefields of Ireland, shoulder-to-shoulder with the Archdruids of the Abrahamic religions in their learned beards and come-dancing gowns?

This time, surely, the sensible majority will make itself heard.