When the third world war comes I'm going to be so sorted. No one is going to draft me off to be cannon fodder on some miserable mountainous front in the middle of nowhere, because I'll be tending you needy lot back home; and when western society crumbles under the military might of the developing world and their Blue Peter homemade chemical bombs, I shall have some of the most sought after skills on the post-holocaust market. For those of you who may require my services, I shall be somewhere in Kent, and I would advise you to start stockpiling the tinned caviar and cigars now, because money will get you nowhere.

Seven of my patients in A&E have now claimed responsibility for the terrorist attacks in America, and I must confess I have taken rather a free hand with my medical judgment and not called in the CIA. Generally, I think it's best to be straight with people, whatever they say, but it's also safer to be polite and non-confrontational if you want to avoid getting a knife in your thigh.

The latest, introducing himself as Elvis Presley, was very keen. "But you are the seventh person I've met this week who's said that," I offer, hoping to broaden the conversation out, as well as gently challenge his opening gag. But he foils me straight off and lets the diagnosis out of the bag with his second line. "Look," he says, fingering his pockets and sneering. "I'm mad, and I've got a knife. OK?"

Now, it must be said that people who describe themselves as mad in A&E rarely are, much in the same way that people you meet at parties who describe themselves as bonkers are rarely not boring, particularly if they do unconvincing Elvis impres sions every time you turn your back. Furthermore, people who really have knives usually just pull them out and have a go, or so I am told by people much harder than me.

Having always been rather lucky with violent patients (and being generally a bit of a nice guy all round) I have to say that one of the greatest joys of A&E is seeing blokes the size of a shed come in with broken fingers from their latest thuggish exploit, and having them be as charming as little pussycats. In fact, the only people who ever look like they might turn really nasty are the assertive middle class self advocates who expect you to work "collaboratively" with them towards an "optimum health outcome", as we say in our communication skills workshops.

Anyway, the main problem with people who come in pretending to have mental health problems when they're clearly just after a bed for the night, an admission to a psychiatric ward for their own amusement, or something to do when nobody else is around to be interested in their personality disorder, is that it's terribly embarrassing when they turn out to be terribly ill. Particularly, I'm sure, if they end up hurting someone, and particularly if they've been telling you all along that that's their plan.

This, in fact, is the main problem with being an A&E doctor generally. You never see anyone for more than the opening stages of the game, and your main problem is to work out if they're ill, lame, or just pretending. Take, for example, every junkie in the South of England who's been in to see me, with their unconvincing stories of renal colic, demanding huge doses of opiates. Or take the Incredible Burping Man: he had been burping incessantly for a week. "I think he's just got no manners," suggested his girlfriend, and I was inclined to agree, but he certainly was burping an awful lot. For all I know he died two hours after I sent him off home to see his GP.

So, as I ponder whether or not to take my terrorist punter seriously and wake up the mental health "crisis response team" (whose idea of responding to a crisis is to front up four hours later in matching black polo neck jumpers) my punter reminds me of his plans. "If you don't admit me to hospital," he smiles, "I'm going to blow up the motherfucker of all parliaments." He smiles again. "And then I'm going to find out where you live, 'Doctor' Foxton, and blow that up too."

Now, the idea of seeing Bedside Manor going up in smoke is one I find strangely appealing, but there are other doctors who live in hospital accommodation too, and for all I know some of them might quite like the old place. I tell my punter which psychiatrist is on call and pop off to rouse the ironically named crisis response team, but when I return he's done a runner. The nurses giggle as I fill the car park with police cars for the third time this week, but Elvis has definitely left the building.