Prime minister Boris Johnson in intensive care in hospital after coronavirus symptoms worsen

Two uniformed police officers were stationed at the entrance to St Thomas' Hospital this evening where the PM is being treated.

Throughout the day officers and police vehicles could be seen entering and exiting the central London hospital.

But, having been in hospital for tests and observation, his doctors advised that he be admitted to intensive care.

Foreign Secretary Dominic Raab will "deputise where necessary", a Number 10 spokesman said.

A Number 10 spokesman said: "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 has asked Foreign Secretary Dominic Raab, who is the First Secretary of State, to deputise for him where necessary.

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

It came just a few hours after Mr Raab told a press briefing that the PM remained in charge of the Government despite remaining under observation.

The Conservative Party leader is understood to be conscious and has been moved to the ICU at about 7pm as a precaution should he require ventilation to aid his recovery.

Scotland First Minister Nicola Sturgeon tweeted: "My thoughts are with the PM and his family - sending him every good wish."

Business minister Nadim Zahawi tweeted: "Thoughts & prayers for @BorisJohnson & @carriesymonds and their family. I have known Boris for 20 years he is a fighter and will beat this virus."

Chancellor Rishi Sunak tweeted: "My thoughts tonight are with @BorisJohnson and @carriesymonds. I know he'll be getting the best care possible and will come out of this even stronger."

Mayor of London Sadiq Khan tweeted: "Praying for the Prime Minister's swift recovery tonight. @GSTTnhs has some of the finest medical staff in the world, and he couldn't be in safer hands."

The development comes as ministers earlier resisted pressure to set out an "exit strategy" from the lockdown.

At the daily Number 10 news conference foreign Secretary Dominic Raab said the Prime Minister remained in charge of the Government despite remaining under observation at St Thomas's Hospital, London.

Mr Raab faced repeated questions as to how Mr Johnson could cope with demands of the premiership if he was sick enough to require hospital treatment.

Earlier Downing Street, which had previously described his symptoms as "mild", switched to describing them as "persistent".

They included a cough as well as a continuing high temperature, 10 days after he first tested positive for the coronavirus.

Meanwhile, the latest official figures showed 5,373 patients have died in hospital after testing positive for coronavirus in the UK as of 5pm on Sunday - and increase of 439 on the previous day.