ART / Boys will be boys: James Hall on the narcissism of Gilbert & George at the Anthony d'Offay Gallery.

During the Renaissance, a sure-fire method of producing a botched-looking body was to draw a Vitruvian Man. The origin of this particular species was a passage in a treatise by the Roman architect Vitruvius. When laying down the rules for sacred architecture, Vitruvius declared that buildings should have the proportions of a man, since man's body is a perfect model of proportion - with limbs extended, it fits into those ideal geometrical forms, the square and circle.

It sounded great in theory, but in practice, Homo Vitruvius was vertically and horizontally challenged. Leonardo's version is unrivalled, and yet the odd- sized legs and arms are creepily Kali- like. A more run-of-the-mill example is the image in a 1521 edition of Vitruvius by Caesarino. Here a naked man is spread-eagled over a graph-paper grid as though he were being stretched on an inquisitor's rack. As Kenneth Clark observed: 'From the point of view of strict geometry, a gorilla might prove to be more satisfactory than a man.'

This rather discredited genre has been enthusiastically revived by the artistic double act, Gilbert & George. For nearly 20 years, they have been concocting photo-montages in their Georgian house near Spitalfields market in east London. Each work is composed from a mosaic of rectangular images bordered by black frames. When the discrete images are assembled, the frames create an all-over grid. Since the 1970s, the finished articles have become increasingly large, lurid and symmetrical.

Their prime subject matter - or rather, their obsession - is the male body. Gilbert & George focus on their own bodies (they are ever-present protagonists in their own pictures) and on those of adolescent East Enders. Any manipulation or deformation is allowed, just so long as the resultant bodies can be locked into the geometrical scheme of things. Not surprisingly, the artists and their youthful associates often seem more like circus animals than men. The backdrop for their antics tends to be what is to hand - the scruffy streets, tower-blocks, churches and parks of east London. And yet, in one important sense, their home town is a ghost town: it is a world without women.

'Urinal' is a textbook example of their remorseless art. It is the most elaborate photo-piece in their big new show at the Anthony d'Offay Gallery. Sacred geometry comes on strong: the backdrop is a grey Gothic cathedral, parts of which have been tinted yellow. In the centre, however, where a rood screen should be, the mischievous photo-montageurs have inserted what can only be called a rude screen: a tripartite urinal.

Flanking the urinal are the two masters of ceremonies - Gilbert, the short one, stands on the right; George, the tall one, stands on the left. Until now, they have always appeared in their photo- pieces wearing tweed 'responsibility suits'. But here they stand before us in birthday suits, and their skin (for obvious symbolic reasons) is tinted yellow. Looming up behind them are two blown- up images of naked men, visible from the waist down. Gilbert & George are sheltered and framed by their thighs.

The general scheme of things is pretty clear. They are making the time- honoured parallel between sacred architecture and the architecture of the human body. Not only do Gilbert & George slot into the grid, but their relationship to the blown-up bodies, and to the Gothic architecture, is like that of medieval sculptures to their setting. Still, we cannot but notice that this is probably not quite what Vitruvius had in mind. With a nod and a wink to Marcel Duchamp, a urinal is at the centre of things. No doubt they want to show that modern heroes cannot stand to attention all day long - even they must obey the call of nature. And, boys being boys, they are looking across at each other, sizing each other up. George looks slightly aghast. Somehow, the whole body-architecture thing has got horribly out of proportion.

In 'Flatman', the whole relational process starts over again. This time, however, the architectural backdrop is secular rather than sacred. It consists of four leaning tower-blocks placed side- by-side. They are grim grey, but their windows and balconies have been brightly coloured, Mondrian-style. The central blocks are separated by a gap which is filled by a crouching adolescent male, tinted purple, red, green and yellow. Enlarged images of his head have been placed above and below him, and he is flanked by full-length clones. Because the tower-blocks lean back, the implication is that the boy is like Samson, destroying an imprisoning architecture. Looking on all the while are Gilbert & George, their grey heads perched on top of two blocks.

Since their emergence in the late 1960s as 'living sculptures', Gilbert & George have always been regarded as quintessentially English. They are usually thought of as soul-mates of Hogarth, Blake, Dickens - visionary realists. This is hardly surprising when one considers how much of their life and art is bound up with English themes. In an early performance, they dressed up in suits and ties, and repeatedly sung a popular pre- war song, 'Underneath the Arches'. Almost all their photo-work alludes to east London life.

Still, this ignores the fact that Gilbert is an Italian who first came to England in 1968 at the age of 25. Perhaps Italian, more than English culture helps explain their most pervasive theme: homo-erotic relations involving themselves and working-class boys. There is homo-eroticism in both Hilliard and Hockney, but it is set in more civilised surroundings. The source of Gilbert & George's more robust version may well be the Italian writer and film director Pier Paolo Pasolini. Pasolini was obsessed by ragazzi di vita, young street hustlers and rent- boys who lived in the volatile shanty towns round Rome. As Pasolini's biographer, Enzo Siciliano, has written: 'These boys, first seen as possessing a haloed and honeyed charm, are flooded with a light that poisons them, little marble torsos dug from the mud, aggressive but sick, savage and marked by anaemia.' So too, the young East Enders.

Why, then, is Gilbert & George's work so deeply depressing? Mainly because you feel that whatever upheavals or incidents take place, they are irrelevant to the overall balance of power. Come what may, the duo never relinquish control, never really change the formula. All symbolic roads lead to them, in their trivial and intractable maleness. Their narcissistic cult of personality is akin to that of other would-be Vitruvian Men - the megalomaniac dictators who have their own images manufactured and displayed on an architectural scale.

In 'Urinal', the whole panoply of the Christian Church is made to arrive at a urinal presided over by you know who. The idea is fatuously reductive. Moreover, if it wasn't already out of date, it certainly is now. The ordination of women means that the Church cannot be glibly presented as a men-only club. In 'Flatman', the Technicolor Samson may push over the modernist tower- blocks with their strict geometry, but when he does so, all his movements are determined by an even more powerful system - the symmetrical grid patterning. Sixties Brutalism simply makes way for Gilbert & George's own brand of Brutalism.

Derek Jarman is a contemporary of Gilbert & George. He started out as a painter, and was the first artist to be shown at the Lisson Gallery when it opened in 1967. He has painted off and on ever since, and was shortlisted for the 1986 Turner Prize. His current show, at the Karsten Schubert Gallery, is a personal response to how the media deal with Aids. He has glued photocopies of raucous tabloid headlines on to canvas in a grid pattern. Over the top he has applied a thick, abstract impasto of lurid colours, in which words are scrawled: 'Horror, Sex, Bomb', 'Aids, Revenge, Spread the Plague'.

Jarman handles paint with gusto and panache, creating a fiery maelstrom of colour. But the lingering feeling is that he is not just obliterating the tabloids, but also intensifying their message. This could be because Jarman is far more horrified about Aids than any of the tabloid headline writers. And he has every right to be. He is HIV-positive. This paradox is what makes these pictures moving rather than melodramatic.

Gilbert & George, Anthony d'Offay, Dering St, London W1, until 29 January; Derek Jarman, Karsten Schubert, 85 Charlotte St, W1, until 22 December.

(Photograph omitted)