How to be a NyLon

Plum Sykes is the quintessential English rose; the willowy, glamorous daughter of Sixties fashion designer Valerie Goad and publisher Mark Sykes. She was brought up in Kent, is a graduate of Worcester College, Oxford, and the girlfriend of Toby Rowland, dashing dotcom entrepreneur and son of Tiny.

But as she floats into the tea-room at the Ritz, she doesn't look British at all. She's lived in the States for the past seven years, and the long, immaculately straight brown hair, slender body and grown-up pastel attire - Manolo loafers, eau-de-nil Chloe trousers, peachy chiffon shirt, strings of diamonds and pearls around the neck - scream New York chic.

Just sitting next to her makes me feel fatter and frumpier than you could believe possible. 'I dress more like a New York girl than a London girl,' she agrees, 'thank God.'

She's over here partly to see her boyfriend, partly, it seems, for a rest cure from her frenetic New York lifestyle. 'For me, London is like a nice country village,' she explains. 'It's so much quieter here than it is in New York.'

Nowadays, she says, she feels like 'a complete foreigner' in London. 'It's because I say what I think,' she says. 'English girls smile sweetly and pretend; Americans enjoy their lives more because they won't suffer in silence. I'd rather live like an American.

'I'm used to getting things done quickly, whereas the English way is to sit down and have a cup of tea first. Sometimes I think it's a shame that I'm not like that any more - but I'm not.'

So it's not surprising that, after weeks of flat-hunting in Chelsea, she's decided to put her plans on hold. 'I've suddenly started thinking I really ought to buy somewhere in New York instead,' she says. (At the moment, she rents an apartment in the West Village.) 'I couldn't possibly live in London anyway, it would be death to my career.'

For the uninitiated, Plum became the toast of New York when she hit town in 1997. Invited to all the glamorous events, Plum's observations on New York society became a column, Fashion Fiction, in US Vogue. Now she's produced her first novel, Bergdorf Blondes, a chick-lit fantasy about Park Avenue Princesses (PAPs), their obsessive beauty routines and disastrous love lives, which has just been published. It netted Plum the unprecedented advance of £350,000 from Miramax and has already been decreed New York's 'chic read of the spring', according to Bergdorf Goodman Magazine.

Plum, 34, decided to write her book in the aftermath of September 11. 'It was really depressing in New York,' she explains, 'and I wanted to read something to distract myself. But everyone was reading Atonement or The Corrections and chick-lit was so badly written. I thought, God, I wish there was a modern-day Breakfast at Tiffany's - something silly and escapist, smart and witty.' Failing to find any, she decided to write one herself. 'I laughed for about a year while I wrote it,' she says.

The book, which follows the antics of a British-born, New York-based fashion writer so thinly disguised that she's actually called Moi, is based on Plum's own close observation of the PAP brigade, much facilitated by her job as a writer and columnist for US Vogue. She tells me about a wedding that she was invited to cover in the Dominican Republic; the father of the bride, a Cuban sugar baron, chartered a 747 for his daughter's guests. Plum, sitting next to two Balenciaga-clad examples of the genre, overheard one complaining: 'I wish we were on a private plane.' 'But you are on a private plane,' Plum riposted. 'No - a private private plane.' 'Dialogue like that was too funny and good to waste,' she says.

It's the sort of spoilt-brat behaviour that, in this country, is thankfully still reserved for a minority of insecure celebrities and socialites. But Plum's intention in writing Bergdorf Blondes is certainly not to allow us to feel superior to our shallower sisters across the ocean.

Au contraire, as Moi would doubtless say: Plum feels we have a lot to learn from them. Mostly in the grooming department. When she arrived in the States in 1997, she was amazed, she says, at how straight everyone's eyebrows were. Within a month, she, too, was down the eyebrow waxer for her regular appointment; her soaring brows are now approximately half the width they used to be. Her wardrobe underwent a similar metamorphosis, from 'London flea-market rose prints' to a glossy uniform of cashmere jumpers, slim designer skirts and polished boots.

'People say that New York girls can look bland,' she goes on, 'but I think they look great. American girls aren't afraid of showing off their glamour, wealth and love of fashion. Over here, the Queen and your cleaning lady dress the same way. People are afraid to stand out in case they are told they are vulgar and brash. Everyone here thinks Posh Spice is incredibly tacky, but I think she carries it off very well.'

Plum does speak with some authority: it was only two years after her arrival in Manhattan that she found herself on the best-dressed list. Subsequently invited on to the committee to nominate future recipients of the accolade, she suggested Kate Moss, only to be told 'but she's so dirty', which rather sums up the difference in approach on the other side of the Atlantic. Yesterday, she goes on, she dined at The Ivy with an English and an American girl. 'Everyone was in jeans,' she says, 'except my girlfriend Blair, who was in a black, one-shouldered silk jersey top, diamonds, a blow-dry and a tan. I saw jaws drop.'

The great thing about American grooming is that you don't have to be beautiful to be considered to look good, she says. So what are the essentials of looking good New York-style? Mostly, it seems to be down to what you do with your hair, wherever it grows. And, leaving aside the waterfall that should flow between your shoulder blades, less is definitely more. Much of Bergdorf Blondes is devoted to discussion of the Brazilian (giving rise to one of the heroine's favourite euphemisms for sex, going to Rio). Has she had one herself? 'Yes, and it was an ordeal,' she acknowledges. 'Gwyneth Paltrow told me to have one. But I don't think it's necessarily an American thing. I was at an English dinner party and asked which of the men wouldn't want their girlfriend to have one. And nobody put their hand up.'

The hair on your head, meanwhile, must be poker-straight. 'You can make a lot of difference with a hair iron,' she goes on. 'Look at Chelsea Clinton. But you have to buy it in New York - the ones you get here don't work.' Then there's the weekly manicure and pedicure, the highlights every 13 days and the visits to the dermatologist - clear skin is a big thing over there. You get your dermatologist on your insurance so you don't have to pay. Acne is considered a medical problem.'

And that's before you get to the exercise and weight maintenance. Plum is a six-foot ectomorph who can eat what she likes and never gain an ounce. 'New York girls want to be really thin,' she says. 'They're much more body-conscious than English girls.' Doesn't she think there's something a little obsessive about this pursuit of beauty? 'I think they do have a tendency to mistake physical perfection for emotional perfection. You have to ask yourself: what's missing that they have to fill the void with all this vanity?' But you can bet your last pair of Manolos that, for Plum, a little more vanity this side of the Atlantic would be no bad thing.