WHETHER it is Tracy Emin's unmade bed or Damien Hirst's pickled cow, it would seem that barely a week goes by without an attack in the media on the world of contemporary art.

Yesterday, a portrait of Princess Diana with blood pouring out of her mouth, painted by former stripper Stella Vine, from Alnwick, Northumberland, and recently bought by the Charles Saatchi gallery was deplored in The Sun as a 'sick portrait'.

Closer to home, in Barnard Castle, County Durham, the Bowes Museum has come under fire for staging an exhibition showing graphic photographs of car accidents and suicides.

Yet despite the barrage of criticism, contemporary art is more popular than ever, with galleries like London's Tate Modern attracting over four million visitors a year. Critics of contemporary art say it is only designed to shock and create a reaction. While modern art lovers argue it is precisely these qualities which give it its appeal.

Paul Usherwood, an art historian and art critic from Northumbria University says that very often media and exhibitions often create the controversy for extra publicity.

The 1997 Sensations exhibition is a perfect example of this, he said. This exhibition drew headlines for, among other things, Marcus Harvey's giant portrait of moors murderer Myra Hindley painted using children's handprints, and Marc Quinn's Self, a frozen replica of his head made from eight pints of his own blood.

"I think amongst newspapers, there's a way of covering contemporary art, which is to look for the most controversial things and seize on it," says Mr Harvey. "At the Sensations exhibition some of the work was really quite conventional. But to give a show of young British artists that name, suggests shock and outrage is going to be the order of the day."

DESPITE the criticism received from some quarters for the After Life exhibition at the Bowes Museum, director Adrian Jenkins feels it is the duty of modern art to provoke questions. He says: "In the museum we also have paintings of Jesus Christ stapled to a cross. I think the imagery in this exhibition is relevant and there to be discussed.

"We have to make a decision whether it is simply gratuitous or not. You have to strike a balance. Contemporary art knows it's going to get knocked, but if it causes debate it's doing its job."

Mr Usherwood agrees and says: "There's a time honoured tradition of avant garde art going back to the 1800s which seeks to undermine, challenge and test normal standard ways of looking at things.

"The Myra Hindley portrait did have serious aspects, making people look again at news photos and the way they are composed of little dots and how they achieve iconic status. Also, it was so big the face almost dissolves into something abstract like some of Warhol's portraits."

Josie Bland, a lecturer in art and design at Cleveland College of Art and Design, feels that often contemporary artists are taking established artistic traditions and looking at them in new ways.

"Several years ago the Bowes Museum actually displayed Damien Hirst's sheep in formaldehyde in conjunction with a stuffed sheep they had in their own collection," she said. "In Victorian times, people would go and look at a sheep like that in a voyeuristic way and I think Hirst was working in that tradition.

"Like Tracy Emin's bed - in expressionism people are revealing themselves and they can do it by paint, or by showing the result of a night of no sleep and tremendous emotional pain fuelled by drugs and alcohol."

THE empty plinth at Trafalgar Square is expected to be the scene of more controversy as one of the favourite designs to be placed there is a sculpture by Quinn, says Mr Usherwood. He says: "It's a statue of a friend of his who is pregnant and severely disabled with no arms. Again people are going to see this as deliberately shocking, or a way of breaking taboos and asking questions."

However, both Mr Usherwood and Ms Bland feel the controversial Body Worlds exhibition at London's Brick Lane stopped short of being art. The exhibition, by a German professor of anatomy, Gunther von Hagens, featured human cadavers which have been 'plastinated' to preserve them. The bodies are then arranged in various positions with their internal organs and tissues displayed for public viewing.

Mr Usherwood says: "Art asks questions and I don't think this really does that, it's more like a freakshow. Although he claims it's educational there are people in the scientific community who don't agree with him. I think he's a chancer."

Ms Bland agrees that while dissections and autopsies were the basis of a lot of training for many classical artists such as Leonardo Da Vinci, the work of von Hagens does not qualify as art. She says: "I don't think he ever set out to pass it off as art. While there is a crossover between arts and sciences, I don't think this is it."

However, van Hagens does have allies in the art world. Sarah Simblet, a teacher at Oxford's Ruskin School of Drawing and Fine Art, says: "It's the first time it has been truly possible to open out the body into space. Many have attempted this, but none has truly succeeded."

In 1989, the art world was the centre of controversy after Canadian artist Rick Gibson was fined £500 after being found guilty of outraging public decency. Gibson's work Human Earrings was a pair of freeze-dried human foetuses pierced through the skull and hung from the ears of a plastic mannequin.

He claimed he was trying to shock people into an awareness of the plight of human foetuses by using a visual image.

While Ms Bland believes that sometimes there is a need for artists to draw a line over which they do not go any further to shock people, she feels it is more the duty of the artist and the art-viewers to exercise self-censorship. "The question is how do you decide who draws your line," she says. "Within contemporary art galleries, a lot of people who by and large don't agree with what is in there wouldn't go there anyway."

HOWEVER, despite the relentless criticism of modern art in certain parts of the press, Mr Usherwood feels that it is becoming harder and harder to shock the public. On the contrary, as the growing number of visitors to the Tate Modern attest, the public enjoy seeing it.

"Some of the people who do really try and outrage people and break taboos are the Chapman brothers," he says. "For instance, their entry at this year's Turner Prize was the Goya pictures that they defaced and the blow-up dolls having sex. But that particular game of theirs is very hard now. It's very hard to upset that particular knowing crowd."

In a 1995 article, 'Unpopular Culture' David Bachelor, a sculptor who works at the Royal College of Art, sums up the public attitude to modern art.

"The Turner Prize ...works as a kind of blind date between recent art and a wider audience, producing the usual array of mismatches, gaffes, bad jokes and awkward silences typical of such encounters," he writes.

"While the particular structure, timing, organisation, and coverage of the prize is constantly criticised, revised, re-examined, re-interpreted and re-presented, the founding idea - that it is virtuous to bring current art to the attention of more people - is rarely questioned."