A “minor” operation on Johnson’s sinuses was performed early Monday morning and Johnson returned to Downing Street to recuperate, his spokesman said.
During the operation, Johnson was given general anesthesia, his deputy is Deputy Prime Minister Dominic Raab.
The prime minister is expected to chair Tuesday’s cabinet meeting, but his return to work will depend on how he feels, the spokesman added.
“It is my understanding that there is a 24-hour period from the moment the operation is carried out … during which important decisions will be deferred, probably primarily to the Deputy Prime Minister,” a spokesman for Johnson said, according to PA.
“Now we don’t expect any of this to be required at this time, but we have the option,” they added.
The operation was planned earlier and carried out by the UK National Health Service.
Johnson is expected to attend the Commonwealth Heads of Government Meeting in Rwanda later this week, and his party also faces two important local by-elections on Thursday.