Naomi's new game

'My plane was delayed for five hours, because of the snow in Paris,' she explains politely. 'And sorry we're doing this on a Sunday, but I thought it would be better because my phone wouldn't be ringing all the time.'

Now the mildest-mannered supermodel might be pardoned for tetchiness having just stepped off a transatlantic flight that's taken twice as long as it should have done. And, as we all know, Naomi is no stranger to air rage.

But au contraire, she seems positively perky. 'I really enjoy travelling,' she says chattily, her low voice a starry amalgam of Streatham and LA. 'I think it's because when I was six months old, my mum decided to take me travelling with her. When I came to the US when I was just 16, I was never worried about being in a different country, and I think that was a big factor. I'm not a model who's been able to make my living in one country. I've always done jobs in many different places.'

Besides, she says, on a plane she gets time to chill out, which must be no small treat for a woman with a life as overcrowded as hers. Take today as an example: after our interview, she's off to make a documentary about black beauty with one of her mentors, the Sixties black model, now agent, Bethann Hardison, a long-time campaigner for greater racial diversity in fashion. Then there's the top-secret fashion shoot (involving 28 other models) that she's got to do; and, of course, the shows that she has to decide whether to grace with her presence or not. (She's decided not to strut the catwalk this year, she says, but she hopes to pop into London Fashion Week if she can get back from her shoot in time.) And she's just about to launch her 11th perfume.

At 38, an age when most models are considered geriatric, Naomi clearly has no intention of putting her career on the back burner. Her top beauty tip, she tells me, is the 'master cleanse' detox diet, which requires her to survive on maple syrup, senna tea and cayenne pepper, and on the day we speak, she's in the middle of it. 'It's quite hard doing it in the winter,' she sighs.

I'd read that with the arrival of the teenage black model Jourdan Dunn on the catwalks and magazine covers, Naomi now felt happy about retiring and handing over her crown. She greets this suggestion with an irritated snort. 'Jourdan Dunn isn't Naomi Campbell,' she says tartly. 'I've never said I'm retiring, And if I did want to stop working, I'd just do it quietly. Because if you change your mind, you're going to have a hard time going back. I love what I do.'

Poor Naomi: she wouldn't be human (let alone the tough cookie that she clearly is - you don't get a seat at the supermodel top table for over two decades without having sharp elbows) if she didn't feel just a little irritated by the headlines hailing Dunn as the new Campbell. But to her credit, Naomi sounds the soul of grace and sincerity when she says that this is what she would like to be remembered for: 'fighting for black models to be accepted. It makes me feel happy to see Jourdan get covers and awards. I'm just so thrilled.'

At the latest Hermès show in Paris, she says, she took a snapshot of herself with the six other black models who also appeared. 'Seven black girls in one show, that's a big deal,' she cries excitedly. 'It was absolutely great. I didn't want to let the memory go.' Is it odd, I wonder, after years of being the modelling world's tantrum queen, to find herself a role model for the next generation? She laughs a little nervously. 'I try to keep it real,' she says wryly. 'I'm a role model that can tumble. I'm not perfect.'

That, of course, is something of an understatement: it's not just last year's air-rage incident, which happened after BA lost her Louis Vuitton bag and she lost her rag to such a degree that she ended up having to do community service. She seems to be forever hurling bejewelled telephones at people who annoy her, which is why I'm glad I'm at the other end of the line, thousands of miles away. Only this year, she finally settled out of court with a former maid who claimed she hit her when she couldn't find a pair of her jeans. I've been strictly warned off discussing these subjects with fiery Naomi, but I'm not sure I'd have dared anyway.

Since meeting Russian property billionaire Vlad Doronin, known as 'the Donald Trump' of Russia, at a party thrown for her by Dolce & Gabbana last year, however, Naomi appears to have mellowed somewhat. At any rate, no more phones have been launched, so far as we know.

She is coy about discussing their relationship but has described the 47-year-old as 'a wonderful man, a very special man' and 'a gentleman'. He doesn't hold back from conspicuous displays of affection either, as when he splashed out on a £25,000 couture gown for her during a charity auction. 'Naomi needs a relationship with someone who is nice, and she should forget about running around with famous men,' American Vogue's Grace Coddington once declared, and following high-profile but failed flings with the likes of Joaquin Cortes, Robert De Niro and Mike Tyson, it may be that Naomi is at last ready to take this advice.

Doronin, whose property projects include Moscow City, a spectacular Canary Wharfstyle development, has the dual advantage of having more than enough money (estimated at £1.5 billion) to keep up with his inamorata's gilded lifestyle, without wanting to divvy up the limelight. No wonder she seems able to contemplate settling down with him in his futuristic Capital Hill home, which has a master bedroom suite perched 60ft above the rest of the house.

'I would like children one day when God thinks I'm ready,' she says. Does she think she'd be a good mother? 'I don't know. I'd have to wait and see. I can only go from my experience about how I was raised and the discipline I had. But I'd like to have a lot of fun with my kids,' she says, perhaps slightly pointedly. Because you get the feeling that her own childhood can't have been all that much fun, despite all the travelling.

She was born in Streatham and never knew her father, who disappeared when her mother was four months pregnant (hence, say the armchair shrinks, those relationships with older men). Her mother, a dancer, was often away; sometimes Naomi would go, too, or she would be left with her grandparents.

After this unsettled early childhood, she was sent to the Italia Conti stage school, where she was taught harsh lessons early on about disappointment. 'I learned how to deal with things at theatre school,' she tells me. 'If I didn't get something, that helped me. I've had many people say, "You can't do this," but I've never accepted "No". I believe there's a way around everything.'

At the age of 15, she was spotted in Covent Garden by a model agent, and whirled away to live out the modern Cinderella fantasy. In many ways, her displays of unrestrained diva behaviour are exactly what you'd expect of that overindulged teenager. What is greatly to her credit is that she appears determined to work her fame and success to achieve more than merely free clothes and entry to every VIP area she fancies.
After seeing images of the destruction wrought by Hurricane Katrina, she set up Fashion for Relief and persuaded her fellow models to strut their stuff for a fundraiser. 'I have a lot of energy,' she says, 'and when I put my mind to something I do make it happen. I call everyone up - Trudie Styler is always so supportive, and Philip and Tina Green... we look at it as our fashionable contribution.' This charity fashion show has become an annual event. Last year, profits went to The White Ribbon Alliance, a charity that aims to cut mortality rates among pregnant women and newborn babies around the world. Its patron, the Prime Minister's wife Sarah Brown, has since become a friend. 'She's extremely real,' says Naomi, 'and very compassionate and passionate about what she's doing. Whenever I have ideas, I send her e-mails.'

They last met up at the recent Davos summit, at a dinner for the WRA which Naomi attended along with the likes of Wendi Murdoch and Queen Rania of Jordan. 'I've been to Davos a few times,' she says casually, 'and this time I thought I'd take advantage and see some other panels. After all, they're making decisions that affect the rest of us.'

Suddenly, I'm seeing a whole other side of Naomi - the canny businesswoman cum elder statesperson. I suppose you don't end up with an estimated £30 million in the bank without knowing what you're doing, no matter how beautiful you are.

This rather more serious role appears to be taking off as swiftly as her early modelling career. She's been to Downing Street, and graciously gives the nod to Gordon. 'I think he's a very approachable, nice man, but he's got a lot on his plate. He's just trying to make Britain a better place,' she says.

Understandably, she's a little more excited by Obama. 'Martin Luther King said 40 years ago that this would happen,' she says. 'It's incredible.' Presumably she hopes to meet the new president? 'Oh, I already have,' she says casually, 'at a party Oprah Winfrey had at her home in Santa Barbara.' Naomi partied alongside Tina Turner, Chaka Khan, Beyoncé and Michelle Obama, and also hung out with Mrs Obama's plus one at the ball.

'He's very nice and approachable,' she says with a giggle of the new president, 'and he's got an amazing smile, and he loves his wife. And look what he's done. He's proved to so many people against the odds that if you always believe in your dream and don't get put off or sidetracked, you can make it happen.' It is indeed an amazing thing, the Obama effect: in this brave new world, even La Campbell is affable and on time. Almost.

Hair by Daniel Dyer at Terrie Tanaka using Frédéric Fekkai. Make-up by Ashley Ward at CLM using Lancôme.
Fashion assistant: Orsolya Szabo