Boris Johnson

Downing Street said he was moved to the unit on the advice of his medical team and was receiving "excellent care".

Mr Johnson has asked Foreign Secretary Dominic Raab to deputise "where necessary", a spokesman added.

The prime minister, 55, was admitted to St Thomas' Hospital with "persistent symptoms" on Sunday evening.

The Queen has been kept informed about Mr Johnson's health by No 10, according to Buckingham Palace.

World leaders - including US President Donald Trump and French President Emmanuel Macron - have expressed their support for Mr Johnson.

He beat Jeremy Hunt comfortably, winning 92,153 votes to his rival's 46,656.

The former London mayor takes over from Theresa May on Wednesday.

In his victory speech, Mr Johnson promised he would "deliver Brexit, unite the country and defeat Jeremy Corbyn".

Speaking at the Queen Elizabeth II centre in London, he said: "We are going to energise the country.

"We are going to get Brexit done on 31 October and take advantage of all the opportunities it will bring with a new spirit of can do.

Sir Michael, writing in the Sunday Times, said the Kremlin was responsible "by proxy" as the "principal backer" of President Bashar al-Assad's regime.

It comes after Foreign Secretary Boris Johnson cancelled a visit to meet his opposite number in Moscow.

The attack has been widely blamed on the Syrian government.

In a previously unpublished column he penned in February, Johnson -- now the UK's foreign secretary -- urged Britain to stay in the EU, just two days before he came out against the Remain campaign.

Mr Johnson, who led the campaign for Britain to leave the EU, will also meet with US Secretary of State John Kerry.

Ministers will discuss the Nice attacks and the defeated coup in Turkey but have stressed there will be no formal discussions about Britain's EU exit.

Mr Johnson's journey to the talks was delayed after his plane had to make an emergency landing.

He replaces Philip Hammond, who becomes chancellor. Ex-Energy Secretary Amber Rudd is home secretary and Eurosceptic David Davis is the Brexit secretary.

Ex-chancellor George Osborne was fired, the BBC's Laura Kuenssberg said.

On arriving at Downing Street, Mrs May vowed to lead a government that works for all, not just the "privileged few".

The UK's second female prime minister promised to give people who were "just managing" and "working around the clock" more control over their lives.