Sargeant, who has worked alongside Ramsay for 13 years, will leave Gordon Ramsay Holdings (GRH) at the end this month to join pub group the Swan Collection as creative director.
His resignation follows months of speculation after his departure from Claridge's earlier in the year and a rumoured fall-out with Ramsay. It comes just months after GRH head of operations, Gillian Thomson, left the group to join contract caterer Company of Cooks.
Sargeant first joined Ramsay at Aubergine in the 1990s. He went on to work as sous chef at Gordon Ramsay's flagship restaurant on Chelsea's Royal Hospital Road before becoming head chef at Gordon Ramsay at Claridge's, where he won a Michelin-star in 2002.
Sargeant has been instrumental in GRH's roll out of its three London pubs, the Narrow in Limehouse, the Warrington in Maida Vale, and the Devonshire in Chiswick, and has worked closely with Ramsay on his many cookery books.
Sargeant said he had had the "most incredible 13 years" working with Ramsay.
"I am hugely proud of the part that I have played in the growth and success of GRH," he said.
Sargeant will join the Swan Collection next month. The company currently runs the Swan at the Globe Theatre, London and the Swan, West Malling, Kent.
However, he will remain "closely associated with GRH" through his continued work on Ramsay's publishing and television work.
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