Heston Blumenthal's gourmet restaurant has been closed after a vomiting virus outbreak.
The TV chef apologised to customers at his exclusive two Michelin-starred Dinner, which will remain closed for a week after 45 diners and members of staff were infected with norovirus.
A council spokesman said 24 diners and 21 staff had been taken ill.
Staff were asked to wash their hands more often, and hygiene improvements have been made, he said.
It is the same vomiting virus which forced him to close another restaurant, the Fat Duck, five years ago.
The award-winning Fat Duck, in Bray, Berkshire, was left out of action for two weeks in 2009 follwing an outbreak of the winter bug that left over 500 people feeling sick.
Speaking to the Mail on Sunday, the 47-year-old said his personal experience and knowledge of the virus meant he knew that it was best to "err on the side of extreme caution".
"I am very sorry for the inconvenience to those customers affected by cancellations," he said.
"However, I will reopen the restaurant safe in the knowledge that we have done everything we can do to continue to strive to create the perfect environment and food for my guests to enjoy."
Blumenthal said that he aimed to amaze guests with "taste sensations beyond their imagination" rather than exposing them to a "really nasty couple of days of heaving".
A total of 24 diners and 21 members of staff were taken ill at the restaurant in the Mandarin Oriental hotel on Hyde Park, Westminster City Council said.
James Armitage, the council's food safety manager, said: "Test results this week have shown that there has been an outbreak of norovirus at the Dinner restaurant at the Mandarin Oriental Hotel in Knightsbridge.
"The operators have now temporarily closed the restaurant and we believe this is the responsible thing to do.
"Westminster City Council food safety officers have already carried out a thorough inspection of both the restaurant premises and working practices and will continue to work closely with Public Health England and the restaurant operators until the restaurant is given the all-clear.
"We have already asked the restaurant to improve some of its hygiene procedures - including telling staff to wash their hands more often. All the changes were made immediately."
Dinner's website said that it was expected to remain closed for a week from today.
Opened to critical acclaim in 2011, the restaurant specialises in historical English food and caters for about 1,000 customers a week.
A meal for two can cost around £190, and signature dishes include the Meat Fruit recipe from 1500 - a chicken liver mousse made to look like a mandarin orange.
An investigation into the Fat Duck outbreak in 2009 found that norovirus was brought into the restaurant by shellfish contaminated with human sewage.
The three Michelin star establishment was shut for 10 days, with 529 customers reporting symptoms in what was one of the largest known outbreaks of the bug in a restaurant.
The highly-contagious norovirus is the most common stomach bug in the UK. It causes vomiting and diarrhoea and can be spread from contaminated surfaces and equipment or if an infected person does not wash their hands before handling food.