Boris Johnson is recovering from a "routine operation on his sinuses" this morning, Downing Street has said.
The Prime Minister's spokesman said Mr Johnson went into an unnamed NHS hospital in London at 6am and he was back in Downing Street by 10am.
Mr Johnson is "feeling well'' and he is due to take meetings this afternoon, No 10 said.
Deputy Prime Minister Dominic Raab is on hand to assist with any major decisions, in line with advice on not making significant choices for the first 24 hours after having an operation under general anaesthetic.
No10 said Mr Johnson remains Prime Minister and will continue acting as such.
Mr Raab previously took charge when the Prime Minister was in hospital with coronavirus in April 2020.
The PM's spokesman said: "The Prime Minister this morning had a very minor routine operation related to his sinuses.
"He went to hospital around 6am and the operation was carried out first thing this morning.
"He was back in Downing Street shortly after 10am this morning."
When asked who would be in charge while the PM recovers, the spokesman replied: "As you know, we follow the standard processes for things like this.
"Effectively, we have the Deputy Prime Minister who was aware of this in advance and the Cabinet Secretary."
Mr Johnson was given general anaesthetic for the procedure, the spokesman added.
The PM is due to chair a Cabinet meeting on Tuesday, and to travel to the Commonwealth Heads of Government Meeting (CHOGM) in Rwanda later this week.
Asked if it was certain Mr Johnson would return to work tomorrow, the spokesman added: "I think it will depend on on on how he feels."
The operation was on the NHS and was scheduled "for a while", he said.
Mr Johnson's sinus issue is not understood to be related to his bout of Covid in April 2020.
The Prime Minister was taken to St Thomas' Hospital in London after his Covid symptoms worsened.
He spent three nights in intensive care before being move back to the general ward.
After being discharged, he released a statement praising the NHS staff who cared for him.
“I can’t thank them enough. I owe them my life," he said.
