My sister Suzon was the real beauty of the family — without question. She looked very much like my American father: very fair, almost blonde, with beautiful green eyes. My dad, who'd been a GI during the war, had met my mother in Japan and got married. They moved to Hawaii to bring up a family. I was the eldest, then Suzon, then Naomi, and Steve, who's the youngest. We had a pretty idyllic childhood, living by the ocean, wearing our bathing costumes to school and playing on the beach.

By the time I was 25, I had become a successful model, I'd moved to London and I was married to David Bailey. In the meantime, Suzon had fallen in love with an American guy and they were doing the hippie trail between Bali, Goa and Jamaica. We remained very close. She'd come and see me whenever she could and wrote letters to me all the time. What I loved is that she'd use turquoise ink and turn her dots into flowers — that always made me smile.

In July of that year, I'd been in Paris with Bailey shooting the collections. The night before we left, we'd had a terrible row. It was so bad, I went back to our flat and drank a whole bottle of vodka. I cried until I fell asleep on the floor. I didn't normally drink; I don't know what came over me. The following night, we got back to London, late. I was feeling down, but my eyes lit up when I saw a package with a Jamaican postmark. I thought it was from Suzon, though there was no letter. Inside was a pair of worn brown boots, my size. That package has remained a mystery. No sooner had I opened it than the phone rang. It was Suzon's boyfriend. He was hysterical. "Suzon's dead," he said, over and over again. He told me she'd been out on her bike and ridden over a cliff near their home. It was only a 15ft drop, but she fell straight on her head. He said she was probably stoned. He'd also been stoned, so it was some time before he'd even noticed her absence. He and their housekeeper eventually went out looking for her. When they found her, more time elapsed because there was no hospital in Negril, so they had to take her to Montego Bay by plane. I was numb. I couldn't make sense of these words, and now I had to tell my parents. They were inconsolable, incapable of doing anything. It was up to me to bring my 23-year-old sister home.

In my head, I have relived the next few days over and over again. Arranging for her body to be cremated in Jamaica; having her ashes flown back to Hawaii; collecting her urn at the airport; holding it in the back of the car; putting it in my closet because nobody could bear to see it. My father's strict southern Baptist upbringing had left him hating the church, but we still held a moving non-religious service, which included a beautiful poem by Kahlil Gibran. As for her ashes, we'd all agreed there was only one place where we should scatter them: the stretch of ocean next to our home in Hawaii, near to Moanalua Bay. There, we knew, she would never be far away.

Bailey couldn't be there, because he was on a job, but afterwards he took me away to try and get some kind of peace from it all. But you don't get away, do you? The grief, guilt, pain, the anger, the rawness, it spills out of you wherever you are. He also wanted me to see someone, but I wouldn't — I never have.

In the end, Bailey, who was fantastic in his own way, didn't know how to deal with me, and our marriage went downhill. I'm not blaming the break-up on Suzon's death, because I was the one who created the problems. But it was a catalyst. It made me realise that while I was alive, I didn't want to settle for second best in anything. I wanted to be on my own. And I'm still on my own today. Sure, I've had other relationships since, but I never remarried and, like my brother and sister, I've never had kids. I don't think about tomorrow. Maybe that's irresponsible, maybe that's bad, but since Suzon's death, that's how I've lived.

Suzon's death changed me for ever. When she died, the Marie I was then died too. I'm sure any psychiatrist reading this would say I'm still damaged. And they'd probably be right. I deal with the pain by not dealing with it. I guess I've got to keep something in control — if I let myself go completely, I'm afraid I won't come back. None of us in my family can really talk about Suzon — even now, 27 years later. But, of course, that doesn't mean she's forgotten — she's never forgotten. She's with me all the time.

Her death is the most monumental thing that has ever happened to me. There's only one thing I know for sure: where I want my ashes scattered — with my sister's. That makes me feel safe. That's the one thing that can't be taken away from me.