Texture and 28°-50° restaurant group co-founder Xavier Rousset has left the business he established with Agnar Sverrisson in 2007.
The restaurateur and award winning wine expert, who has worked with Sverrisson since they met at Le Manoir aux Quat'Saisons, said he was leaving to pursue other projects.
Rousset will retain a small shareholding in the business, but will no longer be involved on an operational level.
In a statement the Texture and 28°-50° restaurant group said Rousset would leave with "immediate effect" and that a director of operations would be appointed in due course.
Rousset said: "With 28°-50° and Texture growing so successfully over the last nine years I believe that now is the right time for me to step down and pursue a new challenge."
Sverrisson added: "Xavier has made a huge contribution to the success of the business. I would like to thank him for his tremendous contribution over the last nine years and wish him every success in the future."
Rousset and Sverrisson opened Texture in 2007 and gained a Michelin star in 2011. The same year the pair won the Best Newcomer Catey.
The first 28°-50° Wine Workshop & Kitchen was launched on Fetter Lane in London in 2010. It was followed by a second London site, in Marylebone, in 2012.
In September 2013, Rousset and Sverrisson opened the 28°-50° Wine Workshop & Kitchen in London's Mayfair.