Surely she could find a cheaper version in a chain store? A copy perhaps? "A copy?" she echoes in disbelief. "It would have to be a very good copy." Her tone suggests that there is no such thing, and she should know. Jenny is clothes crazy. When she isn't at school, she is shopping. Not for any old schmutter, you understand. Names are essential and we're not talking Marks and Spencer. She spends up to pounds 200 a month and "it goes higher if I've got a party. I have to wear something different every time I go out or I'll look stupid."
Jenny is the British Cher - the cool wardrobe-obsessed Beverley Hills chick played by Alicia Silverstone in Clueless, the teen movie of the moment. Cher - whose mother died during a routine liposuction - has a walk-in wardrobe and a computer which helps her choose each day's outfit. The film is hilarious, trivial and too, too Californian - when Cher is mugged at gunpoint she's furious at being forced to lie on the ground, dirtying her Alaia dress. It strikes a chord with British teenagers who take fashion very seriously indeed.
Unlike Cher, Jenny cannot afford Alaia. She is forced to borrow her father's mobile phone, and she has a Saturday job to help fund her clothes habit. She would not explain her tardiness to Sir with "I had to visit the bathroom - I was surfing the crimson wave", and would never refer to the babe who looks fine from afar but a mess close up as a "Monet" (to Jenny, the unfortunate girl would be a "dog").
But, like Cher, she is a likeable fashion expert who is utterly intolerent of boys who wear ridiculous back to front baseball caps. If romantically approached by such a creature, both are likely to utter the crushing: "As if!"
Being chic requires dedication. Jenny and her friends, Nicky Petty (14, tall and svelte) and Sara Stone (14, petite and voluptuous) spend their weekends in Selfridges, Oasis, Morgan, River Island and Next. Nicky confesses: "I go on little shopping sprees. Sometimes I spend about pounds 70 per week. I've got Levis and all the name jumpers like Naf Naf. Everyone recognises them and everyone knows you've paid a lot for them." She adds: "If you look good you feel happy with yourself. I do get clothes from Top Shop but I prefer the names. You're safe with names." Unfortunately, if the trend setters - the fashion media and other bullies - say that Kickers (approx pounds 69.99) are in, so many image-conscious teenagers will blackmail their parents for a pair that their cool-rating soon drops. Who wants to wear what the class loser's wearing?
So Sara's mother Marion wears her daughter's cast offs. Today, she is dressed in a smart pair of black leggings embroidered with a beaded logo. "Sara threw these away," she explains. "They're 'obscene' because they're last year's. She wore them once." Nicky's mother Pam encourages her daughter to buy stuff from the market. As if.
Pam should count her blessings. In Clueless, Cher and her buddies can always dress to the max because there is no school uniform. Nicky and Sara have only the occasional non-uniform day. "It's like a fashion show," says Nicky. "You go shopping specially. Even though there aren't any boys around. If someone turns up in something really dodgy everyone will be going 'she looks a state'. You've got one day to impress everyone, otherwise everyone thinks you're really sad."
Sara's schoolmates are more forgiving: "I go to a grammar school. A lot of people are more worried about their work than what they wear. Some of them turn up in some extremely strange things." Sara raised her neatly plucked eyebrows, adding: "A lot of them don't care about the things that we care about, like boys and clothes and make up. There are girls who have never worn make up! I look at them and think 'my god, you look about 10!' "
There is, however, a difference between looking a mess and looking an expensive mess. We are in Nicky's room. Nicky and Sara sit in front of the mirrored wardrobe and discuss their icons. Nikki Taylor is "beautiful". Kate Moss is "pretty" and Liz Hurley has "her own style". Bjork, however, is sartorially challenged. Sara says: "I tuned into MTV and she had on a luminous yellow plastic dress. It was horrible. She always looks a right state." Nicky disagrees. "Ye-es," she says, "but it's a designer state."