When I was about 15 I had a crazy best friend. He would go out on the street and tell people that the TV show Candid Camera was filming near by and then suggest that they act up for the camera. And they would. They’d go for it, none of them stopping to think that in Candid Camera the victims found out that they were being filmed only after the practical joke. I’d join in with these pranks, sometimes, always with my heart pounding, terrified at being seen through and beaten up. My best friend’s name was Ashley Baron Cohen.

It’s a very strong gene, the Baron Cohen one. Ashley is Sacha’s cousin and, like all of them, tall, striking and possessed of a kind of insane mental energy. Brüno, Sacha’s new film, comes out this week. I saw it in Los Angeles at its first public screening two months ago and the audience were the most excited I’ve ever seen in a cinema.

Going to a Sacha Baron Cohen movie is not like going to see other comedy movies, where the audience laugh, then they watch, then they laugh again. At his films you will hear no space between the laughs; they just roll and roll, building to hysteria, closer to a storming live comedy gig experience than a cinema-going one.

Mostly, he achieves this through just being funny — he is dedicated to funny, refusing to be drawn away to the sirens of sentimentality and earnestness — but also, of course, shock. As well as the straight laughter that his films elicit, there is another kind, more like a gasp or a jaw-drop. Brüno is his most shocking film so far, not because of its “offensiveness”, but in terms of the danger he puts himself into.

There were moments at that LA screening, even though I knew he was OK and that he was sitting a few rows behind hiding his face under a baseball cap, when I had an urge to pull him away from the action on the screen before he got killed.

Where does it come from, the Baron Cohen barminess? Sacha is, of course, Jewish, but his work doesn’t exactly fit into the classical tradition of Jewish comedy: it is visual and physical rather than wordy; stunt-based rather than cerebral; his characters are glorious fools who you laugh at, rather than wits who you would laugh with; and, most significantly, it is big and broad and madly confrontational.

I mean confrontational in the most straightforward way. Loads of Jewish comedians have been confrontational,but on stage, intellectually, artistically. Lenny Bruce may have challenged the taboos of his time, but he wouldn’t have risked tricking a bar of Midwestern rednecks into singing Throw the Jew Down the Well”. Nor would he — the moment in Brüno that most made me want to check that Sacha was still alive — have dressed up as a gay Chassid to poke fun at Osama bin Laden’s fashion choices while in Beirut with a hostage-taking terrorist.

Most Jews are fine with challenging people’s preconceptions, but not up to the point of having all their bones broken. Trust me, it’s unusual so to risk physical discomfort: I have to lie down in a darkened room if I get indigestion.

Of those few Jewish comic performers who stand apart from the main tradition — Jerry Lewis, Mel Brooks and, supremely, Andy Kaufman — none has taken it quite so far, or risked their personal safety so much, as this bourgeois boy from Hampstead Garden Suburb.

But here’s the thing about Sacha. He’s not just Jewish; he’s half Israeli. So ask yourself: which Jews are not full of self-doubt; which Jews aren’t frightened of confrontation; which Jews are, not to put too fine a point on it, a bit mental? Yes. Sacha Baron Cohen is the Mossad of comedy, fearless, up for a fight, havoc-causing, secretive, and often, pissing a lot of people off.

He plays with a lot of stereotypes in his work, but the one he has turned around is his own, the idea of the Jewish comedian as a version of Woody Allen — neurotic, shy, talky. He is the anti-nebbish. I just hope he doesn’t end up at war with Iran.

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