British Prime Minister Boris Johnson has been moved to an intensive care unit in hospital after his novel coronavirus symptoms worsened, Downing Street said on Monday.

A No 10 spokesman said: "Since Sunday evening, the prime minister has been under the care of doctors at St Thomas' Hospital, in London, after being admitted with persistent symptoms of coronavirus.

"Over the course of this afternoon, the condition of the prime minister has worsened and, on the advice of his medical team, he has been moved to the intensive care unit at the hospital.

"The PM is receiving excellent care, and thanks all NHS staff for their hard work and dedication."

Johnson, who was tested positive for coronavirus 10 days ago, has asked Foreign Secretary Dominic Raab to deputise for him where necessary.