All mouth and no trousers

Eddie Izzard's Lenny Bruce may bare all on stage, but we never quite get the naked truth, says John Peter.

Prophets and jokers are both necessary and dangerous, and you invariably get the ones you need, fear or fancy ‹ depending on your moral stance and the state of your mental health. The key to both is subversion. Laughter and enlightenment both represent energies held in check by convention. Prophets and jokers unlock the secret chambers of repression and release energies that ruffle the guardians of smoothly run societies. Was Lenny Bruce, né Leonard Schneider (1925-1966), one of them? This is one of the questions behind Julian Barry's play Lenny (Queen's Theatre), directed by Peter Hall.

Prophets with a sense of humour are rare. A joker exposes his own weaknesses as well as yours, but being a prophet is a serious business that cannot afford the compromise of self-exposure. Moses, John the Baptist and Mohammed never said anything to amuse their followers, and Jesus Christ, who began his earthly career as a prophet, is never described in the New Testament as laughing or even smiling. No, prophets with a sense of humour belong to more secular ages. Jonathan Swift was one. Voltaire was another. Friedrich Nietzsche was one, too, though Nietzsche's humour often feels like being tickled with the barrel of an assault rifle.

Lenny Bruce was a joker who probably aspired to the condition of prophet. I say probably because I do not think he ever quite got his act together. Barry's play is a collage: part life story, part nightclub act and part obscenity trial in which Lenny (if I may) defends himself before David Ryall's not unsympathetic but increasingly exasperated judge by presenting some of his notorious acts and arguing that they were not really offensive.

The play reminds me of Peter Shaffer's Amadeus, a work Hall has directed more than once, in which another young man with a genius for upsetting people and conventions is confronted by a repressive society in a state of outrage. Both plays are short on rounded characters, and both work in short, jagged scenes that are put together not so much as an organic whole but as a theatrical demonstration: this, you see, the playwright says, is what happens when an irresistible subversive meets an immovable system. This is why, in the end, both plays are compulsively theatrical without being fully dramatic.

The difference, of course, is that Mozart also had a genius for something other than upsetting people, whereas with Lenny upsetting people was the aim‹that and the public satisfaction of his own private obsessions. AII prophets have obsessions, usually moral ones, which drive them almost with the force of biological urges. This is why prophets are necessarily cruel: biological urges have no knowledge of moral inhibitions.Eddie Izzard's Lenny is short on cruelty. His body, which is frequently seen completely unclothed, is fleshier than Lenny's, who seems in his photographs to have been lean, almost whippet-like. (Prophets are seldom fleshy and never fat. I never saw Lenny, and nobody under 55 is likely to have seen him, which means that for most of Izzard's audience the problem of physical likeness does not really arise. What is missing from his performance is the sense of cruelty, to wards himself as well as others: the dark flower of an obsession that seems to have been crucial to Lenny's personality, public and private. There is a sophisticated geniality about Izzard, a beady-eyed generosity to wards his victims, which needs to be suppressed. I think Lenny was scary: Izzard can be driven, almost manic, but never scary.

Partly, all this is Barry's fault. The text does not give Izzard and his director enough continuity to work through. Lenny has virtually no private self. His marriage and divorce, his relationship to his family, are briskly sketched in, purely functional like illustrations to a DIY booklet. To talk always about "them", somebody tells Lenny, "is rather paranoid"‹ but the writing gives no hint of the self-destructive poison of paranoia, hardly even of anxiety. Lenny's language was scabrous, filthy, full of disgust and self-disgust: here it is almost tame. Also, the play is too laid-back and long: 10 minutes could easily be cut from each half.

William Dudley's set consists of large sliding glass panels and mirrors that function as both nightclubs and courtrooms: the sort of places where you become dangerously transparent and defensive, where you observe both others and yourself and are observed by others in turn. Some of the characters playing legal parts wear half-masks: I can't think why. It does not add anything to the play or highlight anything in it; it is simply a tired, old-fashioned device that went out with the alienation effect, socialism and free school milk.

Where the production becomes really gripping is in Lenny's great set pieces of moral indignation cunningly disguised as outrageous humour. Here, Izzard, the master stand-up comedian, comes triumphantly into his own. The great compulsive broadsides against sexual and religious hypocrisy cascade from him like streams of gourmet poison, great glittering riffs of black laughter and fury. What English stand-up comedy I have seen, including Izzard's own, usually has a strong element of the conspiratorial: the entertainer knows exactly how far he can go and still be loved. Max Miller is the paragon of this genre. (Lady on the tube: "Is this Cockfosters?" "No, madam, the name is Miller.") There are only a few thrilling moments in this show when Izzard stops being the entertainer and becomes what Lenny was: an obscene, liberating enemy of public morality, the prophet as joker.

Lenny worked in that dangerous strip of land, prickling with moral antipersonnel mines, between actions and the words you use to describe them. Why exactly is it an offence to use the word "cocksucker" in public? According to the rules of public morality that accused Lenny of obscenity, it is offensivebecause it offends people, so there. In this way, silence acquits, just as certain words can be used for purposes of sanitation. This is not only a sexual matter. The Nazis called Jews vermin, but the actual extermination programme was politely called The Final Solution. Its successor today is ethnic cleansing. In sexual morality, too, things have not changed that much since Boccaccio, one of whose narrators in the Decameron remarks that women like to hold in their hands what they are ashamed to name. In Shaftesbury Avenue we are all very liberated, but how acceptable would this play be in Grantham say, or Berwick-on-Tweed, or any Irish town outside Dublin? In the early 1960s, Lenny was refused entry into Britain by the Home Office because he was "an undesirable alien", and from the Home Office's point of view, this was entirely reasonable. Of course Lenny was undesirable. Today's Home Office does things differently: after all, they admitted Augusto Pinochet. But quite a few town councils up and down the land would still ban Lenny if they had the power and if there were a second coming.

Being a prophet, though, with or without jokes, can be a thankless business. Swift and Nietzsche both went insane, perhaps partly because the liberties they craved and argued for, social and political in Swift's case, intellectual and spiritual in Nietzsche's, were finally out of reach. And perhaps Lenny's increasing drug addiction and his wretched death from a morphine overdose, too, were a sign and an admission of defeat. We still do not quite know what freedom is. Lenny's case is not proven either way.