For almost a decade, the mysterious theft of a reservation book from the top London restaurant where Gordon Ramsay made his name has baffled the culinary world.

An unidentified man pulled up outside the Aubergine restaurant on a scooter, dived in, snatched the book - in the days before computerised bookings, a serious act of sabotage - and bolted.

Ramsay, then head chef, pointed the finger at his mentor turned nemesis, Marco Pierre White, who, he believed, wanted to depose him and take over the Michelin starred Chelsea restaurant.

The person behind the 1998 robbery was never identified. Until now. "It was me," Ramsay has admitted. "I nicked it. I blamed Marco. Because I knew that would fuck him and that it would call off the dogs ... I still have the book in a safe at home."

He arranged for the biker to steal it, he explained. "It was my one stroke of genius, fucking someone over without his knowing that I was the one who done it. And the [restaurant owners] cutting Marco off and wanting to get closer to me, kissing my ass ... You always eat that fucking revenge when it's cold, don't you? Trust me, this was stone cold."

The confession appears in an interview published in today's New Yorker magazine, in which Ramsay attributes much of his success to White, who he said taught him everything he knows about cooking. The two stopped talking several years ago.

"All it has done for me is confirm that what I did - cut the umbilical cord - was the right thing to do," White told the Guardian yesterday, responding to the admission. "If this is genius, it confuses me."

White denied ever having plotted to take over Ramsay's job at Aubergine, and said he felt "vindicated" by his former student's confession. "[In 1998] it bothered me that I'd been accused of theft. But it was totally inconceivable - implausible. What would my gain have been to behave like that?"

He added: "If that's how you pay back your friend, and people who've helped you, that's sad. But I've always said ambition is one of the most dangerous preoccupations in the world."

A Scotland Yard spokeswoman said yesterday that police could not rule out reopening the nine-year-old investigation into the theft. "Any new information that comes to life will be considered," she said.

The confession comes as Ramsay opens his first pub, The Narrow, in Limehouse, east London, today. Britain's richest chef, with an estimated wealth of £60m and nine Michelin stars, Ramsay has opened 12 restaurants, four named after himself.

He was unavailable for comment yesterday, but admitted he has taken a gamble in the magazine interview. "Oooh ... even now it sends a chill down my spine," he said. "Because it would have been all over if I'd been caught. But that's the risk you take, isn't it?"

Four months after the reservation book was stolen, tension between Ramsay and the Italian backers of Aubergine and its sister restaurant, L'Oranger, boiled over. Resistant to the idea of turning the restaurants into a chain, Ramsay resigned. His staff also resigned en masse, following Ramsay to a restaurant he opened under his own name.

The New Yorker's Bill Buford, who has shadowed Ramsay since the opening of his New York restaurant, Gordon Ramsay at the London, said the confession came during a "caffeine high".

"One of Gordon's endearing qualities is that he hides nothing," he said. "There wasn't even a beat's hesitation. I asked him [who stole the book] and he said: 'I did it'."

The Manhattan restaurant has received mixed reviews since it opened in November. Critics have attacked the menu, service and decor. One compared the "rarely memorable" food to the cuisine served aboard cruise ships.

Ramsay, arguably as renowned for his expletive-laden outbursts in the The F-Word and Ramsay's Kitchen Nightmares as his food, admitted that he expected to be "kicked in the nuts" during his attempt to conquer New York. "I have been. I have also been knocked down."