BORIS Johnson has fuelled the controversy over Donald Trump’s unexpected decision to pull out of a visit to the UK by claiming Jeremy Corbyn and Sadiq Khan, Labour’s London Mayor, were putting the UK-US Special Relationship “at risk”.

Suggestions have been made that the US President pulled out of his visit to open the new American embassy in London’s Nine Elms near Vauxhall next month because of the prospect of mass protests, raising doubts that the planned four-day state visit will ever go ahead.

After Mr Trump took to Twitter at 4.57am to confirm his visit cancellation, Mr Khan welcomed the news saying the President had “got the message from the many Londoners who love and admire America and Americans but find his policies and actions the polar opposite of our city's values of inclusion, diversity and tolerance”.

Noting how Mr Trump would have been met by “mass peaceful protests” if he had turned up in London in February, Mr Khan added: “This just reinforces what a mistake it was for Theresa May to rush and extend an invitation of a state visit in the first place. Let's hope that Donald Trump also revisits the pursuit of his divisive agenda."

But the Foreign Secretary took to Twitter to condemn Mr Khan and his party leader, saying: "The US is the biggest single investor in the UK yet Khan & Corbyn seem determined to put this crucial relationship at risk. We will not allow US-UK relations to be endangered by some puffed up pompous popinjay in City Hall."

Downing Street was unable to say whether Mr Johnson was speaking for the Government, stressing how it was “not aware of the circumstances of the tweet”.

Asked if the PM felt Mr Khan’s comments damaged the Special Relationship, her spokesman said: “No. The US and UK are strong, resilient partners and allies; we do more together than any other two countries in the world.”

In his tweet Mr Trump said: "Reason I cancelled my trip to London is that I am not a big fan of the Obama Administration having sold perhaps the best located and finest embassy in London for 'peanuts,' only to build a new one in an off location for 1.2 billion dollars.

"Bad deal. Wanted me to cut ribbon-NO!"

The deal for the new embassy was struck in 2008 by the administration of George W Bush before Mr Obama came to office.

Asked if the PM was still confident the Trump state visit would go ahead after the President cancelled his February working visit, Mrs May’s deputy spokesman said: “The US is one of our most valued allies. The invitation has been extended and accepted. No date has been confirmed.”

Asked if it was a discourtesy to the Queen for Mr Trump to keep putting off the state visit, he replied: “An invitation has been extended and accepted and we will set out details in due course.”

Meanwhile, there was some criticism of Mr Trump describing the new location of the US embassy as “off-location”; its current home is in the heart of the West End in Grosvenor Square.

Ravi Govindia, leader of Wandsworth Council, said if the south-west London area had been off-location yesterday, "it is certainly centre-stage today".

Just south of the River Thames, the cube-shaped embassy building is in sight of Westminster and part of a 561-acre regeneration project set to transform one of the South Bank's last remaining industrial stretches.

"The US ambassador has spoken about the pride he and his staff feel in their new embassy,” noted Mr Govindia.

"Not only are they moving to an iconic new zone one building that's closer to Downing Street than the current embassy, they're also are part of the £15 billion transformation of this part of central London that's bringing 20,000 new homes and 25,000 permanent jobs.

"It is also where tech giant Apple is moving its entire UK operation so it's clearly not an off-location for them."

Steve Pinto, Wandsworth Chamber of Commerce chief executive, said the redevelopment would transform the site into a "new centre for London".

Asked if he agreed with Mr Trump's assessment, he said: "No, it's a great deal. It's a terrific deal for Wandsworth. We are really pleased to have the American embassy there, it's fit for purpose.”

Asked about the PM's views on south London after the President described the embassy's new site as "off location", her deputy spokesman said: "Vauxhall is a vibrant and important part of London and home to many businesses; obviously, Apple are moving their headquarters there."

Aydin Dikerdem, a Labour councillor for Queenstown, said Mr Trump was not welcome in his ward.

"The new embassy is 15 minutes from Parliament; we all know why he cancelled this visit. He cancelled this visit because he knew there would be mass demonstrations if he dared to come to the opening. He is not welcome in London and he certainly isn't welcome in Queenstown," he added.