For more than a decade, Marcus Wareing was Gordon Ramsay's publicity-shy "shadow", toiling over the stove for up to 18 hours a day to meet the exacting kitchen standards set by his motormouth boss.
Today, in a decisive shift of reputations, Wareing will be shown to have spectacularly outshone his best man and former mentor: his Knightsbridge establishment, Petrus, has been named best restaurant in the capital.
For Wareing, publication of Harden's 2009 London Restaurants – based on the reports of 8,000 diners – is a sweet moment in his simmering professional rivalry with Ramsay, whose company he will leave next month after a long and messy split.
For Ramsay, still the dominant force in dining but with a worldwide food empire and TV career jostling for his time, the demotion is another unwelcome dollop of bad news in a torrid year in which critics have called into question his commitment to haute cuisine.
Ramsay's eponymous place in Chelsea, the centrepiece of his gastronomic reputation, Restaurant Gordon Ramsay, enjoyed the title of Harden's London best restaurant for eight years running. Based on the diners' reports, Harden's 2009 guide rates Petrus first for two of three categories, food and service, ahead of Restaurant Gordon Ramsay and Le Gavroche in Mayfair.
Despite the victory, Petrus – or at least its name –will not stay at its present venue, the Berkeley Hotel. When his partnership with Ramsay ends on 14 September, Wareing will rename the venue Marcus Wareing at The Berkeley.
Ramsay is likely to transfer the name Petrus to one of his 23 other establishments, spanning the UK, Paris, Dublin, Prague, New York, Los Angeles, Japan and the Middle East.
Wareing, 38, has one restaurant, and it is that singular focus which has allowed him to eclipse his mentor for cooking, Harden's suggests. "Restaurant Gordon Ramsay has had a very good innings – eight years at the top – and still maintains very high standards," said co-editor Richard Harden.
"In the end, though, it is hardly surprising that an impassioned individual concentrating on one establishment, such as Marcus Wareing, has overtaken the flagship of an ever more celebrity-driven empire where the 'name' chef is rarely present.
"Indeed, the Ramsay empire's current performance – and in particular the poor standard of the more recent openings – raises questions as to its direction, and its ability to maintain its reputation as an operator of the highest quality."
Wareing said he was "incredibly proud" of the top placing. "It is the culmination of many years' hard work from myself and my team and also comes at the perfect time, as I will open my own restaurant."
He was less circumspect in an interview this month, venting his years of frustration with his testosterone-fuelled, headline-grabbing business partner, whose Restaurant Gordon Ramsay has three Michelin stars compared to Wareing's two at Petrus.
"If he wants me never to get to the status I want," Wareing fumed, "then my advice to him is: put a gun to my head, shoot me, put me in a box and bury me, because if you don't I'll come back and I'll come back. I'll never give up till I get where I want to go."
Gordon Ramsay Holdings pointed out that it still (for another month) owned Harden's top two restaurants, saying such plaudits should outweigh the guide's "inevitably negative spin".