The “minor” operation on Johnson’s sinuses took place early on Monday and Johnson is back at Downing Street recovering, his spokesperson said.
Johnson was put under general anaesthetic during the operation, and Deputy Prime Minister Dominic Raab is deputizing.
The Prime Minister expects to chair his Tuesday Cabinet meeting, but his return to work will depend on how he is feeling, the spokesperson added.
“My understanding is there’s a 24-hour period from when the operation takes place … under which sort of significant decisions would be deferred to probably in the first instance the Deputy Prime Minister,” Johnson’s spokesperson said, according to PA.
“Now we’re not anticipating any of that being required currently, but we do have that capability,” they added.
The operation had been previously scheduled and was carried out on Britain’s 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.