The launch party for Kate Moss's new Christmas range for Top Shop last week was a typically glamorous affair. Supermodels Elle Macpherson and Naomi Campbell rubbed shoulders with the opera singer Katherine Jenkins, the TV mogul Simon Cowell, the actor Christian Slater and, er, the page three girl Keeley Hazell. But even among all this sophistication, nobody could have failed to notice the sweet, diminuative figure of Chloe Green. Not quite seventeen and clutching a mineral water, her long hair a tumble of expensive honey and toffee-brown highlights, Chloe had an assurance far beyond her years, happily chatting to Kate and her inner circle in an animated, though not arrogant, way. But then, if your father is billionaire retailer Philip Green, such self-assurance is in the genes.

Fluent in French, and currently doing English, maths and business studies at school, you could say that Chloe is the real brains behind Top Shop, since she has her father's ear. And, unlike most of his staff, Chloe is completely unafraid of telling Green what she likes and doesn't like in the Top Shop range - not to mention Miss Selfridge, or any of the other chains he owns under the Arcadia umbrella. "Don't you think Chloe has a good eye?" he once asked a hapless journalist on a tour of Top Shop's Oxford Circus store last year. And so she has. How else could she have chosen to wear what turned out to be the best-seller from Moss's first Top Shop range to the launch party back in May? With first dibs on the whole collection, Chloe could have worn any number of outfits, but it was her pick, the one-shouldered white prom dress, that sold best.

Using Chloe as a barometer of what will sell well this Christmas might not be as foolish as it seems. Some might ask what a seventeen year old girl could possibly know about fashion: the answer is, a whole lot more than a 27, 37 or 47 year old. Trends change so quickly these days that, arguably, only the truly young can keep up, and Chloe is nothing if not a dedicated shopper - something she no doubt inherited from her mother, Lady Tina. According to Sir Philip, it is undecided whether Chloe will go to university before entering the family business: he prefers the university of life. "Chloe has to find her own platform, and be respected on her own account - not because she is the boss's daughter", he told me.

Sir Philip is good that way. You would think that a man at the helm of a multi-billion pound empire might have better things to do than talk on the phone to little moi. But no. And, save for one occasion several years ago when he called me a "f***** p****", our relationship has been fairly cordial. Actually, it used to be non-existent until my editor invited him to lunch in our glamorous sixth floor boardroom, but since that halcyon day, he has always exchanged a nod and a wink whenever I see him socially. He hasn't invited me onto his yacht yet, though.

But I digress. If Chloe is to be believed - and she probably should be - the best seller from Moss's new Christmas collection is destined to be the silver and black beaded twenties-style flapper dress that Chloe wore to Annabel's last week. Sir Philip is no doubt ordering more stock as we speak.