British Prime Minister Boris Johnson was taken to hospital on Sunday for tests, his office said, 10 days after he tested positive for coronavirus.

Johnson, 55, announced he had mild symptoms of COVID-19 on March 27 and had been in self-isolation at his Downing Street residence for seven days.

He had been scheduled to re-emerge on Friday after a week of recovery and working remotely, but said he would remain at home because he still had a high temperature -- one of the symptoms.

Downing Street said in a statement on Sunday: "On the advice of his doctor, the Prime Minister has tonight been admitted to hospital for tests.

"This is a precautionary step, as the Prime Minister continues to have persistent symptoms of coronavirus 10 days after testing positive for the virus."

It is understood Johnson's admission to hospital was not an emergency and was considered sensible because of his ongoing symptoms.

Johnson is the most high-profile world leader to contract the virus. His pregnant partner, Carrie Symonds, said she has been ill with symptoms for a week but was now recovering.

Health Secretary Matt Hancock returned to work on Friday after a week at home following his positive test for COVID-19. The chief medical officer, Chris Whitty, has also displayed symptoms.