There’s a queue, so we walk to up to the man wearing a fez who seems to be in charge of proceedings and ask if we have to buy a ticket. “No, it’s free,” he replies, handing a postcard of Kate Moss à la Andy Warhol’s Marilyn Monroe to a passer-by, ‘like all good art should be,’ he adds gravely, giving a curt nod, the tassel on his fez jumping.
We join the queue, noting the faint whiff of vermin. Within a few steps we can see them; thirty or forty sleeping huddled together in a brown ball beyond the glass. One rat wakes, twitches its nose and runs over to the cracked porcelain cup and saucer filled with water to drink, seemingly unaware of its role in an exhibition by one of Britain’s most notorious artists, the culture jamming enfant terrible – Banksy to his mates.

The apparent crude nature of Banksy’s graffiti art has always underlined an acerbic wit and keen eye for satire. Depending on who you’re talking to, he’s an anti-social spray-painting menace or an urban Raphael. Going indoors, to a gallery no less, seems like a conservative move for one whose reputation has been derived almost exclusively from “street cred”. Sure there are rats (they represent “us” of course) but has the man sold out? No time to ponder this however, because we’ve made it inside.

Once we’ve filled out a disclaimer to say we won’t sue when we slip on rat shit and break our hip, six of us are let through the Perspex gate and told we have a full three minutes. We rush off - mindful of the rodents – to different paintings. The Virgin Mary holds an iPod-wearing baby Jesus in one. A lager lout stands defiantly after throwing a chair at the bar window of Edward Hopper's Nighthawks. A CCTV camera sits prominently in a gay pastoral scene. They’re all one-hit gags, but well-crafted and good fun at that. Even the gallery’s alarm system box is framed like a stag’s head.