inside back: Groups form - a dozen or more bad haircuts crowding up to the glass to pull faces at us, take photos, point, fall about laughing

In my week

Neil reclines on a set of ethnic cushions in a white lace Dolce and Gabbana shirt, sunglasses primed against the light which streams through the plate glass. One arm behind his head and his feet propped on the edge of a red wooden bowl filled with copies of The Face, his copy of Macbeth is tucked down to the side of his thigh, out of sight. He's been learning the dagger speech ready for the new term at the Guildhall. "People," he says, "get really fascinated when you're kipping. They form really big knots then. They don't feel like you're looking back at them."

People are forming knots as he speaks. We are sitting in the window of Selfridges being living mannequins, so to some extent we are asking for it. "There was this guy," says Neil, "when I was in here with Lucille one afternoon. He sat down on the bench opposite the window for about an hour, just glaring at us. And then he got up and started banging on the window, trying to get Lucille's attention. He was going "You shouldn't be with that guy! He's mad! You should be with a girl!". He drinks from a bottle of mineral water; it's equator-ially hot and the sweat is pouring off us.

Oxford Street is a classic illustration of crowd psychology in action. As people pass us, they react by pretending they aren't. Nobody walks past a shop window and makes out that they're not looking at it in normal circumstances. But that's what they do: keep their faces pointed forward while straining from the corners of their eyes.

Some stop once they get to the edge of the window, as if convinced that we can't see them there. Others make a couple of passes, burning up the pavement in their frenzy not to seem directly interested. But everyone is unwilling to actually stop and gawp until someone else has given them a lead. When that happens, groups form, and quickly lose their inhibitions: a dozen or more bad haircuts crowding up to the glass to pull faces at us, take photos, point, fall about laughing.

"It really is like being an animal in a zoo," says Neil. "They do the weirdest things, like coming up to the glass and tickling it at the level where your feet are, the way people try to get fish in aquariums to notice them." They resort to less subtle approaches, as well. Some people stick with waving and grimacing; an aged hippy woman with hennaed hair starts writing messages to Neil on the window with her finger. She is, of course, writing backwards; he performs an elaborate French- style shrug. She shrugs back.

Then the ugly boys arrive. Three of them, in Umbro sweatshirts, on the platform of a No 98 bus. They point, and waggle their shoulders with ugly boy gracelessness. Then they jump off, and take turns to walk past the window clutching their crotches. I ignore them. They don't like this, and come back again, taking longer about it this time. Then they get frustrated. The fat one with the shaved head goes over to where Neil is sitting, pulls an ugly face and gobs on the window. They elbow each other in congratulation over this masterstroke of wit, and lope lumpenly off. "We'll have to get someone to wash that off," says Neil mildly.

Nicky climbs in over the backdrop, dressed in party clothes, and drops onto her bum on our side. She usually works on the shop floor, but has been seconded for the week, presumably because she is so beautiful. "It's weird how aggressive some people can get," she says. "I was sitting with another girl, and this woman came along with a baby in a pushchair. She just stopped on the pavement and stood there screaming at us. We could hear her through the glass. She was going "Fuck off, fuck off you bitches" - she kept it up for ages."

Some software salesmen - we can tell they're software salesmen because they are wearing suits and polyester ties - gather to imitate our hand movements and peer down my cleavage. As all women are aware, our secondary sexual characteristics are a source of endless fascination for the weaker sex; usually, though, they limit their activities to sneaking glances when they think your concentration is elsewhere. The fact of one's being on display removes this inhibition. Now the stares are full-on, with transfixed smiles of joy like a kid in a sweetshop. The funny thing is, rather than pulling the old "Excuse me, I'm up here" routine, I find that I don't really mind. It's all part of a day's work, after all.

An old lady with crumpled red lipstick spends five minutes minutely examining every object on display, standing on tiptoes to peer into the bowl, bending down to look at the floor cushions, but never once directs a glance at any of us. A girl in black rushes up to the window, taps on it, and Nicky jumps to her feet. "It's my best friend from when I was little!" she says, then shouts "Meet you in handbags!" and bounces over the backdrop like a young gazelle.

"Oh, look," says Neil. I turn back to the street. A skinny man in jeans with shoulder-length grey hair stands in front of me, waggling his hips from side to side like the serial killer in The Silence of the Lambs. He lifts up his T-shirt to give me a full-frontal of his nipples. Then, laughing, he dances away up the pavement.