Lumb expanded on her announcement in an Instagram post, which explains that she is moving on to spend time travelling and cooking in Asia and the Caribbean. She will officially depart in August.
It is unclear whether the restaurant will keep the same name.
“It is one of the toughest decisions I’ve ever had to make, but I am so proud of what we have achieved,” says the chef.
“It has always been exciting and there has never been a dull moment - the most wonderful journey.”
The 14-cover restaurant, which won ‘Top Gastronomic Experience’ at the 2017 Harden’s London Restaurant awards, will continue to operate with current right-hand man Miles Strotton stepping up to take the reins.
Lumb cut her teeth at the one Michelin-starred restaurant Gravetye Manor, and has worked as a private chef for the likes of the Bamford and Sainsbury families and George Soros.
She rose to prominence in 2009 when she reached the final of the BBC TV series Masterchef: The Professionals.
The Notting Hill restaurant offers a seasonal four-course set menu, which changes daily according to ingredients. Current menu items include Wye Valley asparagus with lovage oil; potatoes in charcoal with Windrush curds and pickled onions; and Rhug Estate milk-fed lamb with celeriac, apple and mint.