Being a graffiti writer is a bit like being in the Mafia: once you're in the gang, you never really leave. Over the years, I've spoken to lots of people who've done graffiti in the past – and even though they have now stopped, they still say it affects the way they look at the world.

The differences between graffiti writing and street art are not clear-cut. But, very generally speaking, graffiti writing has
tagging at its core, and is essentially a text-based gesture, part vandalism, part art form. Graffiti writing is very much a closed subculture, with the 'writers' communicating amongst themselves. To the uninitiated, their tags are little more than abstract scribbles
that don't make any sense, but people within the scene can distinguish between them, and they know who the different taggers
are, what has quality and what doesn't. Street art, on the other hand, is far more open and much more accessible for general audiences. Any lay member of the public can look at street art and potentially get something from it. You could say that street art is basically fine art on the street – usually done without permission.
By far the most famous street artist in the UK, if not the world, is, of course, Banksy. Although he comes from a graffiti-writing background, Banksy's works now fit much more easily into the street-art category. Banksy makes artworks on city walls, canvases, screen prints and sometimes in galleries and museums. In 2010 he also made the Oscar-nominated documentary Exit Through The Gift Shop. He has many celebrity collectors and an army of obsessive fans around the globe. He has an equally big army of obsessive critics. Banksy's works are a mixture of social satire and visual puns, which often have political subject matter. His style is a blunt form of Photoshop graphic, often rendered through stencils, but his works can take any form, from sculptures and animatrons, to reworked found paintings.

Banksy and the media

The media in the 21st century is ever more pervasive. Messages from corporations, governments and all other manner of advertisers are blasted at us from every angle. Just walking down the road in an average metropolis, we receive more corporate data in a 10-minute stroll than the average Victorian would in a lifetime (I have no idea if the statement is true, but it helps my argument, so stay with me). Street art and graffiti break through this barrage of information with unsanctioned, uncommissioned messages.

Banksy has taken this outlaw ethos and structured it through carefully choreographed stunts. Notable examples include: exhibiting a live elephant in a Los Angeles warehouse for his 1996 exhibition Barely Legal; smuggling an inflatable doll dressed as a prisoner of Guantanamo Bay into California's Disneyland; and stealing a British Telecom phone box, chopping it up so it looked like it had been attacked by a serial killer, then returning it to its original spot, complete with pickaxe and fake blood. These stunts are planned and executed with teams of helpers and, in many senses, are completed by the media. They exist in the real world but, equally, they exist on the printed page, television or computer screen. They are artworks designed to be viewed virtually as much as in reality.

Banksy's reception by the media is also something of a contradiction and conundrum. He's very much the lovable bad boy, the acceptable face of 'graffiti art'. And while newspapers will often praise the fact that some 'vandal' graffiti writer has received a custodial sentence for painting on trains, on the same page they will happily reprint the information sent to them by press offices celebrating the latest prank, sale or sighting of a new work by Banksy.

Banksy and the market

Banksy's works on canvas tend to be versions of his street pieces. Precision Bombing (2000), Winnie the Pooh (2003) and Lenin on Rollerblades (Who Put the Revolution on Ice?) (2003) are typical of this. This relationship with works on the street and signed artworks can sometimes be contentious. Due to the number of unauthenticated works and street pieces being sold, Banksy set up the organization Pest Control to verify any works that were claimed to be by him. Works that do not have such verification or which have come directly from the street are unlikely to appear in any reputable auction or gallery. In terms of auctions, the current record for a work by Banksy stands at £636,500 (this was for a set of five canvases sold by Sotheby's). A collaborative work he made with Damien Hirst sold for $1,870,000, while the current record at Bonhams is £288,000 for Space Girl and Bird.

Equally as interesting, to me anyway, is the lower end of the market, which, at least early on in Banksy's career, was made up of fairly cheap limited-edition prints. Obsessive fans of all ages would spend all night waiting outside various pop-up exhibitions for these works, in scenes more reminiscent of an Apple launch or rock concert than an art exhibition. As the demographic and appraise of Banksy's works has grown, the idea of people buying the prints as a bit of fun has perhaps been lost. I remember early shows such as Santa's Ghetto, held above an East London boozer called The Dragon Bar. Even the guy behind the bar bought something, and at 50 notes a pop, why not? I bumped into the same barman a few years later and he told me that he had recently sold the small work, using the proceeds to pay off his mortgage and go on holiday with his wife and kids.

Banksy in an art-historical context

In an art-historical sense, we can place Banksy in a lineage of many artists who have placed their work in the streets without permission. This might include artists such as Jenny Holzer, Barbara Kruger, Daniel Buren, Keith Haring and Jean-Michel Basquiat, to name just a few. From a 'graff-historical' point of view, we might have him following on from the many New York Wildstyle graffiti innovators such as Blade, Quick, Seen, Lee and so on – all of whom are overlooked by the official versions of art history, yet whose impact on the visual language of the 21st century is possibly greater than any other group of artists you could name. Then there are Banksy's links to protest art and to the artist as agitator. In this sense, he follows on, stylistically and ethically, from the likes of Peter Kennard, Martha Rosler and Robert Indiana, among others.

The invisible celebrity

Artists embracing the cult of celebrity is nothing new; think Andy Warhol, Jeff Koons and Salvador Dalí. Where Banksy differs as artist and celebrity is clearly in his anonymity. Unless you have a cape and mask, being famous and anonymous at the same time is difficult to master, but Banksy pulls it off. With a spray can and a cardboard stencil, he and his intrepid assistants traverse the globe, installing their unique brand of wry street art in the most unlikely public spaces. So we have the name, the fame and the myth, but the man himself remains in the shadows. All these contradictions, be they in the work itself, reactions to it or the public persona, can be debated ad infinitum. Ultimately, what is worth celebrating is that Banksy exists. A former graffiti writer who does not play by the rules – least of all, art-world rules – he has become massively successful. He's not going away any time soon.

Cedar Lewisohn's most recent book is Abstract Graffiti (Merrell). He curated Street Art at Tate Modern.

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