'I'm the senior house officer. I've come to do your liver biopsy - but with my hangover I may skewer your kidneys instead'

Informed consent, take one

"Hello, I'm the house-officer and I've come to consent you for your operation. It's called a laparoscopic cholecystectomy. What they do, basically, is make a tiny cut here-ish ... anyway, somewhere in your tummy ... and pump you full of gas. What sort of gas? Ooh, it's a special surgical gas. Then they pop this telescope thingy in, and whip your gall bladder out. How? There's some clawy thing, I expect. Oh, you mean how do they get the gall bladder out through the tiny hole? I'm not sure. Maybe it shrinks on the way out. Anyway, they sew you up, and you'll be home in a week. The consultant said this afternoon? Well, I expect he's right. He's the consultant, after all. No, there aren't any major complications ... your sister had it, did she? She went yellow and died ... well, I expect that's very rare ... ha, ha. No, I won't be doing the operation myself. Yes, it is just as well, isn't it? Now, if you'd just like to sign here."

Informed consent, take two

"Hello, I'm the senior house officer and I've come to do your liver biopsy. Well, that's what I hope I'm going to do. With my hangover, I wouldn't be surprised if I skewer both your kidneys. I do try to limit myself to a bottle of spirits a day but I've been under stress, what with my wife leaving me and having to cover for my registrar who's off sick with depression. I could let the house officer do it, but she's not done one before. Though that's nothing to worry about. She did her first lumbar puncture with the text book open on her knees."

Informed consent, take three

"Hello. I'm the senior registrar. You must be ... (What's her name again? Jenkins) Mrs Jenkins. I was lying in bed last night thinking about your problem and it suddenly struck me. Why don't we fashion a new tongue from your spleen? It's not been done before, but I'm sure it'll be a huge success. Sign here."

Informed consent, take four

"Hello, I'm the anaesthetist. I've got a list of the possible complications of your operation. I'll read them out; stop me if you want to know how likely one is to occur. First there's the risk of dying on the table if Stinky Wilkins is the surgeon, then there's the risk of dying if it's Chopper Harris, then there's the risk that we may run out of oxygen; the risk of the theatre being invaded by locusts ..."

Informed Consent, Take 5

"Hello, I'm the consultant. I'm here to look after you. You leave all the worrying to me."

Thinking of being interfered with by a health professional? Let me remind you of your rights. You have the right to have explained to you, in non- technical language, the nature, purpose and material risks of the proposed procedure. For many medical encounters, consent is implied. If you roll on to your left side, draw your knees up to your chest and take a few deep breaths, it implies that you've consented to a rectal examination (provided you've slipped your pants down). We don't ask you to sign anything before we take your blood pressure, look for nits or squeeze your testicles. Legally, we're skating on thin ice - even to take a pulse without consent is an assault - but the risks are small and time's too precious to ask permission for everything.

However, we have to gain your express consent for anything that carries a material risk, defined as "a risk that a reasonable person in the patient's position is likely to attach significance to". There's a pay-off here between severity and likelihood. Puncturing the bowel during a rectal examination is both very serious and vanishingly rare. So we tend not to mention it. More contentious is the failure to discuss implications. Taking blood pressure is, in itself, safe. But the potential psychological damage of finding you've got a mildly raised blood pressure is never mentioned. If you feel your doctor was negligent in not mentioning a side effect you then suffer, he or she'll not be liable if the court finds that a "reasonable doctor" following the "respectable school of thought" would not have mentioned the risk either. In short, doctors get off.

However, it is worth asking if the person consenting you for your operation is capable of carrying it out. For decades, newly qualified house officers have been turfed out on to the wards to consent the masses for operations they can't do, haven't seen and may not have ever heard of. Take One is scandalously common, and makes a complete mockery of informed consent. Take Two, by contrast, never happens because doctors don't personalise the risks. And yet, if your doctor has an addiction problem or is generally overworked and battle-weary, it could constitute a very real material risk. Consent forms don't guarantee that a particular doctor will be carrying out the procedure and, unless you go private and specifically ask for them, you're most unlikely to see audited results of your surgeon's success rates. As a friend put it; "I haven't got a clue what happens to my NHS hernias. They go back into the community and are never heard of again. I presume they're OK, but who knows?"

Take Three harks back to the glory days when surgeons dreamt up new operations by night and tried them out by day. Some were pioneering successes, others were disasters. They still happen, though we tend to hear only of the successes. There is evidence that informed consent allows patients to participate in, prepare for and recover more quickly from their treatment, but if doctors reeled off every risk and allowed patients to decide which ones were material or not (take four), waiting lists would vanish overnight. Small wonder many patients prefer take five.