Boris Johnson has been admitted to hospital due to coronavirus after suffering 10 days of symptoms including a high fever, bringing doubts about his capability to lead the response to the pandemic despite No 10 insisting it was purely precautionary.

Johnson was taken to an unnamed London hospital on Sunday after days of persistent symptoms, during which time he has been self-isolating. Last week No 10 had denied the prime minister was more seriously ill than claimed.

A Downing Street spokesperson said: “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.”

Officials were keen to stress that this was not an emergency admission, and that Johnson will remain in charge of government, and will be in regular touch with colleagues and civil servants.

If his condition worsens Dominic Raab, the foreign secretary and first secretary of state, is the designated minister to take charge. Raab is expected to chair a 9.15am Monday meeting of the government’s C-19 committee, which leads the response to the pandemic.