The importance of spotting a genuine Banksy, The Guardian

Ignorance can be costly in the Banksy exploitation business. Only yesterday it was reported that "bungling workmen painted over a mural by famed street artist Banksy worth £100,000". Last week, 60-year-old Sam Khan, purveyor of luggage and football scarves to the denizens of Tottenham Court Road, London, was inconsolable after flogging a Banksy that had been painted on his stall for £1,000 and discovering that it could be worth £500,000. Poor love. These stories pose a number of questions. Were the workmen really bunglers, given they were employed to remove graffiti? Does a transient daubing suddenly become art if it is worth a lot of money? Is Banksy's work really worth half a million and, if so, should we pity stallholder Sam for failing to maximise his accidental revenue? Finally, and most importantly, how do we spot a Banksy?

The sad fact is that most original Banksys have now been removed from the streets. Steve Lazarides, his agent (yes, our anonymous-situationist-anarchist-street artist has come a long way), says: "Ninety per cent of Banksys don't exist any more."

There are obvious signs to look out for. The signature - a blocky, stencilled Banksy. (The trouble is, after a while he stopped signing them.) Then there is the subject matter - smiley faces, snogging coppers, little girls embracing bombs etc. (Another problem is that Banksy spawned a generation of copyists, so it's hard to know if a Banksy is really a Banksy.) Lazarides says there are a few genuine ones around - down the road from the Guardian, in Farringdon, is a faux hole-in-the-wall cash dispenser; there's an Apache attack helicopter in Old Street, London; a naked lover hanging out of a window outside a sexual health clinic in his hometown of Bristol; and coppers kissing in Brighton.

Finally, having spotted a Banksy, how do you claim it as your own? Tricky one. Lazarides doesn't have much sympathy with Sam. The thing is, he says, Banksy intended the work for all of us, not just to line the pockets of a fortunate few. "If you really want to claim it as your own, it would often mean nicking a whole building or at least a wall."

For the truly ambitious, once you've spotted a Banksy, you can try spotting Banksy himself. Take note, from the one journalist to have knowingly met him (allegedly): if you see a scruffy bloke who looks like a cross between Jimmy Nail and Mike Skinner, with a silver tooth and a fag in his mouth, a pint of Guinness in one hand and a stencil in his other, it's likely to be the genuine Banksy.