They might look dead, sound dead and feel dead, but you can never really be sure

"Death," a consultant physician once told me, "is when a nurse puts cotton wool in three or more orifices". It's a nice thought, but not one I found much support for from the ward sister. "We do occasionally use cotton wool plugs when we're laying someone out but only after a doctor has told us that the patient is in fact dead."

"And how does the doctor know?"

"I'm not sure - I was told that anyone with five or more tubes in them must be dead, but don't quote me on that."

Suffice to say that diagnosing death isn't easy. It is possible to have three cotton wool plugs in and live (two perforated ear drums and a bloody nose would do it) and sitting on your Pan pipes could send your tube count well over five without killing you (although it might be a tad uncomfy).

Conversely it's possible, even desirable, to die in an entirely plug- free, tubeless zone. And if you're really lucky, you can live through your own death certificate.

Last year, two middle-aged women survived a pronouncement from their family doctor. Both had the good grace not to pursue the matter in the courts and even the solicitors remained restrained, observing that the GP had made "a slight error of judgement." It was left to Labour MP Doug Hoyle to work himself up into a party political froth. "It' s an absolute disgrace and suggests how the Government is causing standards to fall in the NHS." I'm sorry, Doug, but doctors have been misdiagnosing death since the dawn of time and just as frequently under a Labour government.

To the layman, it can be hard to understand how we can get it wrong with such accuracy, but in truth it's an easy mistake to make. Patients who are very cold or drugged can seem dead in the light of the living room. And then there's the problem of hearing the heartbeat. With thin people, the heart is separated from your stethoscope by a couple of ribs and a thin sheet of muscle so it's not too difficult. But in people who really enjoy their food, it goes heart, muscle, ribs, yard of lard. No chance of hearing anything save the odd tummy rumble.

There are, you'll be pleased to hear, more sophisticated ways of spotting death. You pour freezing water in the ear. This is called "testing for the vestibulo-occular reflexes" and, in a living person, should elicit an eye movement. The only time I've tried it, it elicited a headbutt so I tend not to do it any more.

Other death-determining tortures include poking something in the eye ("testing the corneal reflex"), poking something down the throat ("testing the gag reflex"), grinding the knuckles into the sternum ("testing the pain reflex") and squeezing the testicles ("ditto")*. Small wonder most people want to die at home.

You might expect nurses, with their constant bedside vigils, to be rather better at spotting demise but if one ever phones you at three o'clock in the morning to say your aunt's taken a turn for the worse, the chances are she died six hours ago and they've only just noticed. So while you're rushing in to pay your last respects, they'll be popping her in a piping hot bath to warm her up a bit. Then they sit her up in bed with the oxygen mask and headphones on, listening to Radio Bedside, and just as you arrive on the ward it's "Oh, you've just missed her. She's peaceful now."

To be fair, I've not actually witnessed this ritual although I did once work with some nurses who were so convinced a man had died that they taped his eyelids down. Luckily his sense of humour was as black as the nurses', but he did stop taking an afternoon nap.

Less fortunate was my friend Tom who was called to a coronary-care unit to see a large woman who was lying very still. He couldn't hear her heart so he certified her dead and told the nurses to inform the next of kin.

Five minutes later, he was bleeped back to the unit to find her sitting up in bed and reading The Sun - so technically she was still dead. However, when the relatives arrived to find her eating a banana, they quite reasonably demanded an explanation. So Tom looked them in the eye and said: "Well, you see ... there are different stages of death ..." Yep, you can be slightly dead or slightly alive - just don' t expect us to get it right every time.

*I know very few junior doctors who actually do all this. Most just poke their head round the curtains, grunt and nick the grapes.