Gilbert and George's work is seen to be gritty and provocative. But in fact it owes its internationa

Gilbert and George are well known for dressing in suits that make them look like a pair of tailor's dummies from a Burton shop-window display, circa 1963 - the year, Philip Larkin claimed, that sexual intercourse was invented. (In fact, George looks rather like Larkin, and, with their shared love of Mrs T and all things scatological, they might have got on rather well.) They are also famous for being gay; for living in an 18th-century house in the East End of London that is now worth megabucks; for not having a kitchen and eating the same meals every day at local cafés; for being polite and charming to journalists; and for never saying what they really mean or meaning what they say. Most of all, they are known for taking relish in épatant le bourgeois. It is the armature on which their highly lucrative artistic careers have been built.

Those shocked by their vast photomontages littered with giant turds, sputum, spunk, blood and a smattering of pretty gay boys of various races have called them fascist, disgusting and many other things besides. Their supporters counter that they are misunderstood outsiders who make "art for all". Their work, we are told, has nothing to do with the elitist, bourgeois art to be found in Cork Street or the Royal Academy. It can be appreciated by any Tom, Dick or Harry down at the spit-and-sawdust local.

However, with their recent South Bank Show visual arts award, and now a retrospective at Tate Modern, it is clear that the contemporary art world has, in fact, clutched them to its breast. We know this is a "major exhibition" because that is what the Tate has bombastically called it. (Surely it is up to us to decide?) British artists are meant to show at Tate Britain rather than its modern-art counterpart. But Gilbert and George wanted the cathedral halls of Tate Modern and, after a little argy-bargy, that is what Gilbert and George got - two whole wings of the place. The work goes on for miles.

The exhibition begins with a large, pastoral, five-part "charcoal on paper sculpture" (a large drawing to you and me), on which they have written: "WE BELIEVE THAT LOVE is the PATH for a Better WORLD of ART in which GOOD & BAD GIVE WAY for GILBERT and GEORGE TO BE." As heirs to Andy Warhol, they understood from the beginning of their career that irony, enigma and self-promotion were to become the true obsessions of late 20th-century art. Their manifesto of 1969, The Laws of Sculptors, reads:

1. Always be smartly dressed, well groomed relaxed and friendly polite and in complete control.
2. Make the world to believe in you and to pay heavily for this privilege.
3. Never worry assess discuss or criticise but remain quiet respectful and calm.
4. The lord chisels still, so don't leave your bench for long.

In the early performance pieces Singing Sculpture and Underneath the Arches, made between 1969 and 1971, Gilbert and George appear as "living sculptures", part Flanagan and Allen, part Vladimir and Estragon. This set their signature for the next 30 years, with drinking, violence, gay culture, racism and graffiti-scrawled streets forming a grubby backdrop. Photographs of a performance at a railway arch in Cable Street encapsulate certain themes running through the later work: an iconoclastic identification with the outcast, a linking with a specific locality of London and a particular take on Englishness. But, most of all, these pieces show how Gilbert and George became the subjects of their own art.

They went on to use the building in which they lived, working to present themselves as characters from a Sunday-afternoon black-and-white B-movie with Dusty Corners (1975). The piece is evocative, even poetic in an Old Curiosity Shop sort of way, but it was Coming, a 1975 series of nine black-and-white photos of the pair in insouciant poses amid pools of spilt beer (or spunk), fingers loosely held in a provocative V, that was to point the direction of their later work.

Since then, ordinary photographs have given way to slick, technicolour photomontages, hovering somewhere between cartoons and Gothic pastiche, about copulation, coprophilia and death. The run-down inner city becomes a sort of solipsistic, prelapsarian gay playground in which they feature as the main players. To an extent, they are the Joe Ortons of the art world, only without Orton's wit. In works such as Shitty Naked Human World (1994), with its crucifix of four brown turds, and Spit Law (1997), which shows them bent over, baggy Y-fronts crumpled around their ankles to expose their bum holes, the artists are reminiscent of small boys behind the bike shed who think they are being ever so smutty when, in fact, they are simply being boring. Gilbert and George want us to be shocked, but would be rather less happy if they knew that the primary feeling they elicit is ennui.

Another of their obsessions is God and the kitschy trappings of religion. And yet, without a jot of religious doubt or philosophical questioning, religious signs and symbols - crucifixes, Masonic compasses, pseudo-Islamic lettering - are raided like a dressing-up box. Even their recent works about the London bombings, such as Terror and Bombs (2006), seem like cynical appropriations. Theirs is a solipsistic world where there are no women, old people, or even children - no one but them and their cast of beautiful boys. Yet an essay in the exhibition catalogue would have us believe that their art is a sort of expansive humanitarian enterprise, illustrating human frailty and involving a process of "unremitting self-exploration and self-exposure, not out of self-importance or vanity . . . but as an example to others of the necessity for a fully examined life". The case is also made for their multiculturally inclusive approach, evidence of which is the number of black and brown youths they use for their photos. Yet even this smacks of essentialism and exoticisation. If these were images of women made by heterosexual men, would we react differently?

Gilbert and George's work is not objectionable because it is crude, raw, or in-your-face: many paintings by Picasso are cruel and ugly, and surrealism relished the profane and degraded. But with this pair, there is the suspicion that their fat bank accounts and international reputations are supported by the sycophancy of much of the art world. There is nothing real behind these works - no vituperative anger, no despair, no existential doubt, no love or passion - nothing, in fact, that makes art a meaningful and important human activity. That we accept it as great work worthy of such huge space at Tate Modern shows how lacking in confidence we have become about insisting that art should actually show what is painful, true and meaningful. We should not be fobbed off by these ersatz, commodified visions. Oddly, it is the sealed, glossy, sanitised slickness of these works that makes them objectionable, and not their supposedly iconoclastic content.

"Gilbert and George: major exhibition" is at Tate Modern, Bankside, London SE1 until 7 May. For more information visit:

Gilbert and George: the CV

1942 George Passmore is born in Devon

1943 Gilbert Proesch is born in a small village in South Tyrol, Italy

1967 Gilbert and George meet while studying sculpture at St Martin's School of Art in London. Shortly afterwards, they move to Fournier Street in the (then) working-class East End neighbourhood of Spitalfields

1969-70 The duo begin a period working as performance artists with their student creation The Singing Sculpture, followed by a series of live-performance works involving their getting drunk

1986 Gilbert and George win the Turner Prize for their exhibition at the Guggenheim in New York and their major European touring show

1990 They start producing provocative

large-scale photomontages, notably the Cosmological Pictures

1995 The series of photomontages Naked Shit Pictures prompts a media furore

2005 The artists are chosen to represent the UK at the Venice Biennale with a series called the Gingko Pictures. The presentation makes press headlines with a picture depicting the artists flashing the V-sign

Kylie Walker