Bogosian's one-man shows - Drinking in America, Sex, Drugs, Rock & Roll (filmed, to unnerving effect, by John McNaughton, director of Henry: Portrait of a Serial Killer) and now Pounding Nails into the Floor with My Forehead (The Dog Show) - are visceral monologues with a cast of hundreds. In full flow this man is a fearsome sight: his face is bug-eyed and wheedling, his cramped, muscular body tenses and slackens with repellent grace. Bogosian's characters - beggars, drug addicts, hoodlums, casting agents - speak with voices that are pushed one step on from reality, revealing their gluttony, desperation and selfishness with an alarming clarity.
Lenny Bruce and Jonathan Swift are the high-flown comparisons most frequently drawn, but some of his more gruesome grotesques have the pitilessness of Hogarth. Bogosian admits that his characters 'aren't necessarily the nicest people'. 'I think the good side of myself is fairly uninteresting,' he deadpans bleakly. 'I don't see any reason to put that on the stage - as soon as you want to be likeable, you're lost.' As someone says of Champlain, Bogosian's world is 'a nice place to go for a holiday, but you wouldn't want to live there'.
Born of solid American-Armenian stock, Bogosian grew up in a Boston suburb, doing time as a Boy Scout and even an altar boy. Dustin Hoffman in Midnight Cowboy was an early inspiration - 'I had never seen anyone who looked like me act in anything, unless it was some scumbag the Untouchables blew away' - and after studying drama in Ohio, he moved to New York in the mid-Seventies. There he acquired a punk rock attitude, made friends with artists like Cindy Sherman and, somewhat bizarrely, ran a dance project - building up reserves of athleticism that would be useful later on.
His unique blend of spoken word, performance art and stand-up comedy evolved initially from his difficulty getting work as an actor. A prototype character, a Bernard Manning-style stand-up comedian called Ricky Paul, designed to question the liberal assumptions he thought he shared with his audience, met with widespread opprobrium. Bogosian flirted with some of the dissolute lifestyle excesses he has since catalogued. He smashed up a dressing room in Edinburgh once - 'I'm still ashamed of that' - but the unnerving humanity of the low-life voices he picked up from the Bowery near where he lived made him a hit from the first in Britain.
Seeing him perform at the ICA in the mid- Eighties, it was impossible not to be struck by the divergence between the fortunes of Bogosian's characters and those of his audience. He says that the point of what he does is to explore the limits of empathy - 'whether you really do believe in your heart that if fate had dealt you the same hand as these people, you would behave in the same way as they do'. In the comfortable surroundings of the theatre, his ideal of 'there but for the grace of God . . .' all too easily became a freak show which left you feeling more, not less, uneasy.
His new work addresses some of these difficulties. It's subtitled The Dog Show because 'If all we're supposed to do is run around, eat, screw and bark a lot, then dogs are all we are.' This is the first of Bogosian's shows in which the author features as himself, looking over his characters' shoulders.
There is a second shift. 'I was starting to realise that stuff which had started out pretty aggressive and confrontational was becoming just entertainment - 'Do the homeless one, he's very funny' - so the focus is shifting somewhat from the street people to self-satisfied, right-thinking, middle-class urbanites. They're out there in the audience so I might as well throw stones at them too.' This change reflects one in Bogosian's own circumstances. Thanks to Talk Radio and voiceover work he's no longer at subsistence level but now shares a comfortable family life. His wife, Australian- born Jo Bonney, to whom he's been married since 1980, is also his director, with the final say over her husband's word portraits of unrestrained machismo. They have two children.
Prosperity has done nothing to cloud Bogosian's eye, however. His characterisations are as sharp as ever. A self-serving therapist advocates 'getting in touch with the inner baby'. A cut-throat business warrior, armed only with a call-queueing system, dominates colleague, rival, wife, mistress and hard- pressed secretary ('Diane, let me make it easy for you, just put your hand in the microwave and I'll eat that'). Older, street-based routines like the overbearing panhandler survive and flourish - 'I could be holding a knife up to your throat, but I don't want to do that.'
Although this was never explicit, it seemed like Bogosian was dramatising the mean spirit of the times. Did he feel any impulse to change with the end of the Reagan / Bush years? 'I don't think what I do is that topical. Misogyny and racism and homophobia are a part of our culture. People don't seem to change - hate is something they seem to need.'
'Pounding Nails into the Floor with my Forehead', Almeida, N1 (071-359 4404), Tues to Sat.