With malice aforethought: Artists are often the perpetrators of crimes against art, as in the case of Mark Bridger vs Damien Hirst. Tom Lubbock on the iconclastic impulse

Iconoclasm. A child of three could do it. Children often do. But however much distance there may be between a toddler ripping the heads off dolls and the person who - as the papers say - 'goes berserk' in a gallery, the iconoclastic impulse runs pretty deep. It's wrong to think of the vandalism and destruction of paintings, sculptures and other art-objects as simply aberrant behaviour. And it's wrong to think of it as simply a negative response. It is an essential part of the history and the nature of art.

The motive, for one thing, is rarely philistine. Take the casualty list of that mainly post-war phenomenon, attacks on 'controversial' contemporary art: Reg Butler's The Unknown Political Prisoner, battered in 1953; David Mach's Polaris, a giant nuclear sub made of car tyres, set on fire outside the Hayward Gallery in 1983, killing the assailant too; and this year, Damien Hirst's Away From the Flock, drenched in black ink. These incidents are often cited as worrying evidence of British philistinism (though it happens elsewhere too).

But while many are outraged by a waste of public money, and a few are actually against art as such, they're seldom the ones who do the damage, even if they welcome it. The attackers in each of the cases were all artists. The motive may have been artistic conservatism or artistic resentment, but they acted essentially in defence of art - in the cause of 'true' art, in the cause of the sort of art they did, neglected in favour of this stuff. Their motives are very like those of some forgers. But their tactics are worse. Forgers often get famous in their own right. Vandals almost never do. They only make their targets more famous.

And it seems an oddly self-defeating act. For if the provocation is that this sort of art is too easy, that anyone could do it because it involves no skill, then the corollary is that it's the easiest kind of art to restore or replace.

(On the other hand, if you like it, it's the hardest art to plunder meaningfully. Last year Vong Phaophanit's Rice Field suffered a lot of 'grazing'. But what could you do with your handful of rice when you got it home?)

There is another irony to attacks on avant-garde art: the history of the modern avant-garde is itself full of the rhetoric of iconoclasm. Marcel Duchamp suggested using a Rembrandt painting as an ironing-board. The Italian Futurists recommended blowing up the Giotto-frescoed Arena Chapel in Padua. No end of anti-art movements have urged that the museums be put to the torch.

Even so, the anti-art cause was never absolutely anti. One destroys art for art's sake, for the sake of expanded ideas of art. Burn down the museums - because they are the mausoleums of art. Blow up a chapel - it's a spectacle, a happening too. Iron on a Rembrandt - it's 'appropriation' in reverse; if a urinal can be installed as a work of art, why not install a work of art as a household object?

In the 20th century, ideas of creation and destruction have gone hand in hand. Jean Tinguely built machines that destroyed themselves. Lucio Fontana made a career from slashing his own canvases. Robert Rauschenberg created an Erased de Kooning Drawing. And the artist who savaged and then re-labelled the dead sheep was thoroughly in on this game, presenting his action as a way of making the work his own.

Still, one may agree with the art-historian Leo Steinberg that, 'what one ought to dislike in Duchamp's suggestion . . . is ultimately the provincial banality of it. It's been done.' It has, and it continues to be, for many reasons.

Sometimes from sheer indifference: in the Middle Ages many antique sculptures were recycled as masonry. Sometimes it's war: the Futurists only had to wait a little while for Allied bombers to shed their load on to a chapel containing Mantegna fescoes in another part of Padua. In any political upheaval, the statues of the old regime got toppled. Nor have earlier artists held back: David's pupils throw eggs at Watteau's Cythera as a symbol of artistic decadence.

Or it may be done for the highest motives. There was Ruskin destroying Turner's erotic drawings while cataloguing his work. There were Klimt's watercolours, burnt by the Vienna court for obscenity. Or think of the Sistine Chapel frescoes. First painted over in the cause of decency, with drapery to conceal the genitals of the figures in the Last Judgement. Latterly cleaned in the cause of restoration - and perhaps drastically over-cleaned, removing beyond repair some of Michelangelo's original paint.

And then there's iconoclasm proper, and the question of the potentially idolatrous nature of religious images, maybe of all images. In the first millennium of the Christian era the 'Iconoclastic Controversy' was fought out with much actual destruction and with much debate in various Church Councils. The very existence of European art depends on the fact that this debate was eventually resolved in favour of images. This hasn't prevented any subsequent waves of iconoclastic zeal, for example during the English Reformation and Civil War. Witness the rows of decapitated saints in Ely Cathedral.

Today, the predominant idea of art- vandalism is different. We don't think of the collective, wholesale destruction of images, though such incidents do still happen. We think of the individual act - the singular confrontation between the deranged loner, armed with knife or acid or gun, and the unique and priceless work of art. And perhaps it is a distinctively modern phenomenon. Certainly, the selection of targets is affected by modern forms of art-fame: news from the art market and mechanical reproduction. It's the priciest, most postcarded works that get singled out.

And just as some bridges get established as the ones to jump from, so some pictures seem to become established as the ones to assault - sitting targets, an open challenge.

Rembrandt's Night Watch in Amsterdam has been attacked at least four times this century. It's almost a tradition. And paradoxically, since money, fame and vandalism constitute a cycle, damage should ultimately put prices up.

In the London National Gallery, too, it's the major works that have mainly suffered. Poussin's Adoration of the Golden Calf (cut to pieces in 1978), the Leonardo Cartoon (shotgun, 1991) and - an earlier cause celebre - Velazquez's Rokeby Venus, axed by the suffragist Mary Richardson ('Slasher Mary') in 1914. The act was ostensibly a political stunt ('I have tried to destroy the most beautiful woman in mythological history as a protest against the Government destroying Mrs Pankhurst, who is the most beautiful character in modern history'). But was it also an early piece of feminist criticism? As Richardson recalled much later: 'I didn't like the way the men visitors gaped at her all day long.'

Old-master vandals offer various explanations for their deeds. It pleased me to do it. I wanted to harm what everyone else cherished. The work was too beautiful. I am God. And of course they often 'go berserk' - you have to act fast in a gallery. But as David Freedberg points out in the essential book of this subject, The Power of Images, most of these attacks have a common factor, one that's common to mass iconoclasm too.

The target of the attack is not the picture so much as the image. Landscapes and still-lifes are usually passed over. It's figurative works, and the figures in them, that bear the brunt. People go for the face, the eyes or, like Michelangelo's Pieta, the nose. The Venus took it on the back and buttocks. Leonardo's Cartoon was shot through the Virgin's heart. (Admittedly, Michelangelo's David only lost a toe, but up on its pedestal that was the nearest extremity within reach.) As Freedberg says, 'It is perfectly clear that any number of these assaults are predicated in one way or another on the attribution of life to the figure represented.' And the vandal acts from fear.

Some such feeling, he thinks, underpins all our responses to art, and 'the love and fear of images are indeed two sides of the same coin'. The theory won't cover every attack. But one thing can be said for sure about art vandals. No fundamental disrespect is intended. They take art much too seriously.

(Photograph omitted)