What will Katie do next?

For ten years she's ridden every fashion wave, from doe-eyed waif through grunge princess to streetwise sophisticate. Kate Moss can do no wrong. But her latest project, a glossy shampoo ad, is uncharacteristically mainstream, and now there are rumours of a film career. Will Kate keep her cool? asks James Sherwood

WHY IS L'OREAL'S Elvive advert the most talked-about TV since Ally McBeal? Because it stars Kate Moss and because she's worth it. Name just one other girl who can declare war on split ends and keep her credibility. Coming from Kate, victory over problem hair sounds like a monumental achievement. Were Kate to tell us she'd split the atom, let alone a hair follicle, we couldn't be more impressed. Kate Moss can do no wrong.

Kate is the sole survivor of her generation of supermodels. Stella Tennant is pregnant and will be out of action at least for a while, and Shalom Harlow, Amber Valletta and Cindy Crawford are all pursuing the old model- turned-actress cliche. Of the new generation, Karen Elson is over-exposed, and waif-life Audrey Marnay, Cordelia and Angela Lindvall look like pale imitations of Kate's first incarnation as waif princess. Helena Christenson has retired from the catwalk and Christy Turlington is a full-time student, while survivors like Linda Evangelista and Naomi Campbell make the very occasional Cover Girl or catwalk guest appearances.

Kate Moss has served Nineties fashion effortlessly. The public love her because she's always where it's at. If she was a passive fashion Barbie doll, Kate wouldn't connect with us, but she is a whole package; the attitude, the look, and the energy of her time.

"Since her debut, Kate has straddled three completely different fashion movements," says Nick Knight, who first photographed Kate Moss for American Vogue. Moss was the gamine grunge princess of early Nineties recession. She was the face of CK1, the Calvin Klein scent that spelled optimism, inclusion and innocence. Now heroin chic Kate and CK1 Kate have given way to sophisticated high-glam Kate.

It is debatable whether Kate's public forgive and indulge her Elvive performance rather than approve of the new commercial Kate. "The opus of L'Oreal adverts, particularly the `I'm worth it' catchphrase, are a triumph of American madness," says York. "I watch them spell-bound. Americans are taught to have self-worth and American women are taught to assert themselves. When that animated bunny Claudia Schiffer says she is working on her skin, she clearly believes every word of it. America is an `I'm worth it' culture. Britain is an `Excuse me for breathing' culture. I detect a subtle American accent in the Kate Moss advert. Maybe she is moving from `Excuse me for breathing', into `I'm worth it' territory."

The Elvive advert is a key moment in Kate's career. Scene deputy editor Scarlett Brady reports a rumour from the Paris Couture last week that Kate was quitting the business to pursue an acting career. "Kate never was a pedestal beauty," says Brady. "And we expect pedestal beauties in hair and make-up ads. Elvive doesn't work for Kate because she's not a Sindy doll. Part of her appeal is her quirkiness. But when it's projected next to a Cindy Crawford or Claudia Schiffer, you notice she hasn't got fantastic teeth. She's not looking so good. Kate is not a plastic beauty. We don't want her to be. So we are shocked to see kooky little Kate in a glossy ad. Real Kate is the girl in the One-to-One advert. `Victory' sucks, I'm afraid."

Surveying Kate's modelling career, it would be fair to say she's fashion's answer to the Teflon kid. She is a maverick model because she doesn't conform. She's been a scapegoat for anorexia, teenagers smoking and an entire generation's drug abuse. But she was smart enough to keep moving. What she has never been blamed for is selling out to the mainstream.

"She leaves me cold," says Marcelle d'Argy Smith, editor of Woman's Journal. "Kate Moss is an example of mediocrity worshipping its own image. Kate Moss is the face of the decade because we've seen it so often. Andy Warhol over-estimated fame by 13 minutes if you consider it takes just two to walk up and down the catwalk. That's all it takes now. Kate Moss's success is a lottery. It was pure luck."

As a Nineties urban myth, Kate Moss's chance discovery at JFK Airport may be all the more powerful because of her girl-next-door aura. She seems to cut through the artifice in a way her super-model predecessors could never do. Tomo Delancy, who was booker at Kate's London Agency Storm in 1992 when Kate won her first Calvin Klein contract , says: "Kate was a revolution on

the catwalk because she was a 5ft 7ins, average-shaped girl compared to the 6ft super woman. She is fresh, young and unpredictable."

As Scarlett Brady says: "Kate Moss was never intended to appeal to a generation other than her own. It is significant that Kate has been in countless magazine portfolios and always on the catwalk. Big girls don't make money with editorials. Look at the top 10 earners in modelling and Kate's name isn't there. Big girls do make money with campaigns like Elvive. Maybe she is consolidating her worth." The generation who grew up with Kate Moss are her core fan base. They've been through grunge, depression and heroin chic and now they are ready for the sophisticated, grown-up glamour that Kate 98 endorses. But are they ready for movie star Kate Moss?

If modelling is like silent movie acting, then Kate is already a consummate professional. Kate effortlessly negotiates the tightrope between street cred and high style. She can project high voltage glamour for John Galliano's Christian Dior couture shows. She can do raw, edgy London street style for Dazed & Confused. She can wage war on split ends for L'Oreal. But we still think of her as "our Kate". Elvive is one of our few glimpses of all-talking, all-walking Kate. "She has that pretty, ratty British look to her while speaking model-talk in the Elvive ad," says Peter York. "That's the charm of Kate Moss. Thank God she doesn't have those tombstone teeth and racehorse legs. Clearly she's playing with the medium."

"The acting medium has different disciplines," says Nick Knight, who premiered a short film at the Venice Biennial based on an American Vogue assignment with Kate. "But an essential element of modelling is the ability to take on a role. For my second assignment with Kate for British Vogue I worked with a ten by eight plate camera, which is very exacting. It requires a girl to hold her pose and work extremely hard. Part of Kate's skill is her patience and willingness to make a story work. The fashion industry adores Kate. She will be welcomed in the business as long as she is challenged by it. But Kate's talent would translate from stills to moving pictures."

As Peter York points out, Kate Moss is already part of the Hollywood rat-pack by virtue of her relationship with Johnny Depp. However divided opinions are on Kate's Elvive performance, it is to her credit that L'Oreal deemed her worth the direction of cult French film maestro Luc Besson. But even if Kate does make her first movie in 1999, she will have to fight the public's time-honoured cynicism towards the model-turned-actress. "All the girls are petrified of the MTA cliche," says Brady. "But models are an obvious choice as screen stars, particularly in the Nineties. The big girls today are a brand. They are an actual publicity vehicle for film-makers.

"Girls like Kate have a ready-made audience who will be desperate to see her on the big screen. In my opinion, if Kate proves she can act in her first role, then she will make the change. She turned down the lead in David Bailey's new movie because she didn't think she was ready... and very sensible too. But, I have heard she is considering a film role. Kate Moss is not going away. I'm not sure where she is going but it is not away from the public eye."

Modelling years are like dog years - for every one, think seven years of an average career. It is extraordinary, to say the least, that Kate has survived for 10 years total with the unconditional love of her fans intact. L'Oreal Paris general manager Christophe Lequay has his own theory as to why Kate is still relevant in 1998. Now here comes the science part. Concentrate. "Kate is so many different things to so many different people - all at the same time. She can go from being cool, quintessentially English, grungy, chic, spirited, idiosyncratic, glossy to simply Croydon's girl next door... people identify with Kate precisely because she has all these conflicting characteristics."

Kate touches a nerve because she doesn't appear to take fashion too seriously. She is Cinderella with balls and cynicism. Her London booker of 10 years, Jess Hallett, says: "Each individual projects their own values onto Kate." "Kate is one of the few untouched by fashion," says Scarlett Brady. "She's still a South London girl wtihout airs and graces. She has gained sophistication, but she'll still have a laugh with you." "Her understanding of what a photographer wants is faultless," says Knight. "She is very patient and considerate of other people's feelings." Kate's a pincer movement charm offensive. The public don't think she tries too hard, while her fashion peers know she works it for all she's worth. It is a professional and personal double whammy. If she could turn the same trick on screen, then modelling will just be the foreplay in our love affair with Kate Moss.