Katie Grand, the high priestess of British fashion, got engaged while throwing up in a field at the wedding of her friend, the stylist Charlotte Stockdale. Her husband-to-be, Pulp’s bass player, Steve Mackey, held her hair back as he popped the question.

“It was kind of really romantic and really unromantic.” She grins her trademark gap-toothed grin at me. “I’m very rarely sick and Charlotte Stockdale is very rarely sick — but she was sick at my wedding as well. Either one of us was pregnant or we just drank too much at each other’s weddings.”

It was the latter. The marriage took place on July 11, in a romantic church in the middle of Upper Saranac Lake in New York state — a place they had discovered on a previous getaway. The wedding was tiny — the hotel was at capacity with the 35 close friends, family and fashion luminaries that had been invited, so there was a bit of a hoo-ha when Marc Jacobs rang to say he was going to drop by in his helicopter for a surprise visit.

They ate cheese sandwiches and drank 28 bottles of vodka, as well as champagne, wine and tequila, served by David Waddington from the hip London restaurant Bistrotheque.

“It was all a bit much really,” says Grand. “We were in church in the middle of a lake and there was a thunderstorm. I’m not a very religious person, but it was so romantic.

I fainted twice at the altar.” She likes to pretend she is a practical sort, but there is a definite air of the unreal in her voice. “My dad was there looking dead chuffed with all these really dolled-up girls cooing over him.”

Never a slave to tradition, the bride spurned white. “I wore an Azzedine Alaïa brown snakeskin dress, which he tortured me for about two months to get into, but at least it’s something I can wear again. I didn’t want some stupid white dress; it seems like such a waste.

A friend in Birmingham used to make wedding dresses and we’d think it was funny to try them on, these big meringue numbers.” rand’s influence in the world of fashion is enormous. If you have passed a Calvin Klein underwear advert on a billboard or flicked over an Armani Jeans advert in a magazine — she picked the models and the clothes, decided the mood. If you have bought a pair of knock-off Louis Vuitton shoes in the past two years — well, she helped design the original. She may not be a household name, but everyone at some point will have seen, worn or wanted to wear her work. That celebrities and leading fashion designers practically fall over themselves to heap fawning accolades on her bears testimony to Grand’s considerable power. She possesses the mysterious “cool” factor that so many aspire to. Yet, for someone who hangs out with Marc Jacobs, Victoria Beckham, Agyness Deyn and Patsy Kensit, she seems remarkably ordinary.

“We go out every now and then,” Beckham tells me. “I wouldn’t like to say she’s a troublemaker, but it’s always guaranteed to be a lot of fun. I was a bit nervous of her at first, she has such a reputation for being great. I thought she’d be older; she’s so young to have achieved what she has.” Grand styled the Spice Girls in their mid-1990s heyday. “She’s been so supportive of me since I’ve been working in the fashion industry,” says Beckham. “If I have any questions, she’s the first person I’ll get on the phone and say ‘I’m doing this, what do you think?’ She has so many influential people listening to her, and she’s really earned that respect.”

Patsy Kensit agrees: “She’s really kind and not a bitch. I’ve never heard her be horrible, ever. She blows the myth of the ‘fashion person’ out of the water.” The two became friends when a fashion shoot turned into a tequila-drinking session 17 years ago. “I think people can get quite carried away in that role. I always knew she would go on to great things; she always gets it right. I’m not surprised about her success. When I first met her she was just this girl with two bin bags of clothes. She gets clothes delivered by private jet now, but she’s still the same person.

“Her hen night was the best party I have been to recently. It was girls and gays, and Jeremy [Healy, Kensit’s husband] DJed. We danced in the garden way past the wee small hours. It’s become a private joke. We text each other, ‘Are you still dancing in the garden?’ Katie’s just a laugh. She’s a great girl who’s sublimely determined and easy to work with, and there’s no ego — she has the knack of reading people.”

“She is not jaded,” coos Mark Frith, the editor of Time Out and an editorial consultant for Love, the biannual fashion tome of which Grand is the editor-in-chief. “She likes fashion for what it is, which is this fascinating visual world.”

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