It must be 27 years ago that I saw Tom Conti in the role of the patient with a severed spinal cord who asserts his right to choose to die. The play Whose Life Is It Anyway? and Conti's performance have lived in my mind ever since. I looked forward to seeing the revival with the Sex and the City star Kim Cattrall as the paralysed advocate of choice, renamed Claire Harrison. Like visiting a friend I had not seen for years, I was wholly unprepared for the ravages that time had inflicted on Brian Clark's text. Where once the dialogue had rattled along, it now seems to plod. Material that was once fresh and daring now strikes me as musty and trite.

The play has reached a venerable age. Originally a TV play, it was born on Granada Television in 1972 (when Ted Heath was prime minister, if any readers remember him). Theatre in the 21st century moves at a different pace. Playwrights no longer treat theatregoers as quite so dumb. In the intervening years, the issue addressed in the play has become familiar. Stephen Hawking has produced masterpieces of thought, despite having lost the use of his body. Christopher Reeve fought to recover movement after his spinal injury and campaigned to raise money for research. Diane Pretty went to court to claim her right to die. Reginald Crew travelled to Switzerland where he was allowed to end his life. Parliament is legislating on living wills (which would allow people to make their wishes clear before their accident or illness). When the judge in the play says, "This is a most unusual case", it makes no sense. Nowadays, such cases are rarely out of the news.

In plucking this dusty play from the shelf, the director, Peter Hall, could have presented it without modification as a 1970s classic. In fact, Clark's play has been doctored. References to the modern world hang from it untidily like Post-it notes. Thus NHS consultants moan about bureaucracy and accountants. But the make-over is superficial. Some unreformed lines sound as patronising as a Pathe newsreel: "I never met anyone quite like Claire Harrison. She's so bright."

The play is filled with stereotypes. The giggly trainee nurse (played by Emma Lowndes) made me feel uncomfortable, and I am no feminist. The gangly, oversexed, joke-cracking black orderly (Jotham Annan), who has a sit-down whenever he can and gets caught by the sister, is a caricature bordering on the offensive. It only gets worse when Claire elevates him to a sort of hero because he alone does not feel guilt about her condition. Sister Anderson, very well played by Ann Mitchell, is a type straight out of Emergency Ward 10 (1960s television, if you don't know). Those bosomy authoritarian dragons in starched uniforms, who obsess about smoothing sheets but have a heart of gold really, are figures from history. You cannot serve them up in a revival that pretends to be set in a world of stem-cell research and courtroom video links.

Alexander Siddig, playing the hand-some younger doctor who takes Claire's side, struggles to bring life to his two-dimensional character. William Chubb seems to have abandoned any such effort as the consultant who thinks he knows best for the patient. The problem with the script must indeed be enormous for even the big-name stars Amita Dhiri (Milly in TV's This Life) and Janet Suzman, who could do nothing to lighten their leaden roles as Claire's solicitor and the judge. The lawyer's interview with the pig-headed consultant now sounds extremely lame and lacks any subtlety. During the bedside court hearing to decide Claire's fate, I feared the play would grind to a halt completely. Could Peter Hall really be involved with this limping thing? His presence in the audience suggested that it must be more than an ugly rumour.

In fairness, I must record that the performance was greeted with cheers. I suspect they were for Cattrall, who would have received an ecstatic ovation just for turning up. Certainly she did much more than that. She showed that she can do theatre. She mastered a huge part faultlessly. Her head on its pillow above the bedclothes was in constant motion (more than I would expect from a person with a ruptured spinal column, for it seemed to me she moved her chest and shoulders, too). Her vivacious face held our attention and her big eyes lit up the stage.

But I did not like the interpretation. I missed Conti's quiet, sardonic delivery. By comparison I found Cattrall shrill, as though she was trying to make up in volume what she lacked in movement. Not for a moment did I believe that she was paralysed. The glamour shot on the theatre programme's cover does not help to create the illusion. I, who get choked up by Mary Poppins, felt completely unengaged by Cattrall's performance.

I slunk away to nurse my memories of the 1978 production. We should have been left with our illusions. What then seemed like a masterpiece ought never to have been exposed in this revival. Whose idea was it anyway?

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