'Is there a doctor on the flight?" I look up surreptitiously. Episodes such as this dredge up all kinds of ugly feelings in any doctor. It's a cracking opportunity to be a bit of a hero, which we like. And I'm convinced there must be plenty of attractive, single air stewardesses out there. But many doctors, since we're mostly NHS and not privately insured, won't help strangers any more. We've all heard the stories about a friend of a friend who got sued over a minor cock-up in the process of saving a life.

You see, if you're nasty to us, I'm afraid we stop being nice to you. We're too human and too underpaid to subsidise your bad spirit. A nation recoils in indignation. Aren't you obliged to help? What - and get sued? Frankly, no.

So I sit there for 10 seconds, engaging in a self-righteous seethe. They ask again. There is nothing different or special about being a doctor, you know. Plenty of other professions are in a position to relieve the pain of strangers, but choose not to. For example, the person who sits on the check-in desk at the airport, who very nearly buggered my holiday, whose job it is to say things like, "I'm sorry, sir: check-in for that flight closed two minutes ago." Who can listen to a distressed, sleep-deprived junior doctor saying, "But please, you've got to help me: if I don't get on that plane I will lose my girlfriend/only holiday this year," and really mean it. And who didn't care.

The person who does that job has the power to go the extra mile, fix problems, alleviate pain and prevent real, serious damage to people's lives. No, it is not different. It is the same. I straighten my shirt and get up, smiling, to see the patient.

The stewardess heads me off with the medical box and retreats. I glance. It has lots of exciting- looking stuff in it, but none of those nice pocket-sized medical textbooks we occasionally (coughs) like to refer to. That's fine. He's probably just had a heart attack. I catch myself hoping that the bag doesn't have anything too complicated, like IV atropine, or a central line.

I look over the patient. He doesn't seem to be in pain. In fact, he's not moving at all. I touch him and he's cold. He is, on cursory inspection, dead. At this point, I'd like to make clear that, belligerent though I may often appear, in the flesh I am always nice and polite; and, despite my private rant, it took me 15 seconds to get here from the time the announcement was made. Human bodies, I would guess, must have similar heat-retaining properties to the average central heating radiator: they couldn't have got him this cold in less than a quarter of an hour.

I listen to his chest with a stethoscope and all I hear is very loud engine noise. Poor chap. And he was alone.

So I certify him, and scribble some basic medical notes. And then they bring me three more forms. I spend my whole life filling in forms. I was happy to work for free but there is no way I'm signing those forms, on principle. I only came to help out. I didn't do anything as a doctor. He was already dead.

I look at the forms. They are covered in legal words, not medical ones. They speak of liability.

"What about my forms?" They get very insistent. Almost threatening. Everyone is watching. I feel like the in-flight entertainment.

So I sign the forms, and I sit down and seethe until we land. As I get off the plane, the stewardess presses a gift bag into my hand. It contains six laminated drinks coasters and a plastic model of an aeroplane. It looks as if you and I both get exactly what we deserve.