The US embassy in London said its move to a new location has been completed within budget – just hours after Donald Trump described it as a “bad deal”.

Mr Trump has refused to travel to the UK to open the new American embassy, hitting out at its move from Grosvenor Square in the prestigious Mayfair district of central London to an “off location” at Nine Elms, south of the Thames.

Despite the president publicly blaming predecessor Barack Obama, the US embassy said the plan to finance the project was developed in 2007, at a time when George W Bush was in the White House.

Mr Trump tweeted: “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!”

On Friday night, a spokesman for the US embassy said: “The US chancery in Grosvenor Square had aged beyond its ability to be improved to current security and life safety standards without extensive investment in infrastructure that would require appropriated dollars.

“In 2007, the Department developed a plan to finance a new embassy project through a property swap for existing US government property in London.

“This solution allowed construction of a new chancery that meets all security standards, yet used no taxpayer dollars to fund the project.”

The spokesman said the budget was approximately one billion dollars (£730 million) and includes the site purchase, design, and construction costs.

He added: “The project has been executed within the established budget. The search for a new embassy site in London considered more than 50 sites.

“A multi-disciplinary team of professionals considered over 170 criteria, to include physical security requirements, and determined that the Nine Elms site was the best overall location for the US government.

“The new embassy in Nine Elms is one of the most secure, hi-tech, and environmentally-friendly embassies the United States has ever built.

“We are strongly committed in the special relationship between our two countries and we are confident the new embassy will provide the necessary platform to continue our cooperation.”

Mr Trump’s cancellation of a visit to Britain has left the Government and City Hall at loggerheads as Boris Johnson accused London Mayor Sadiq Khan of endangering the so-called “special relationship”.

There was initially confusion as Downing Street was unable to say whether the Foreign Secretary was speaking for the Government when he said Mr Khan and Jeremy Corbyn were putting the “crucial relationship at risk”.

Mr Khan had said the US president had “got the message” from Londoners and would have been met by “mass peaceful protests” if he went ahead with plans to open the new embassy.

A Number 10 source said: “Boris expresses himself in his own inimitable way, but we agree that any risk to the crucial US-UK relationship is not in our country’s best interests.”

A Downing Street spokesman said Mrs May would tell Mr Trump he is welcome in London.

Asked about the PM’s views on south London after the president described the embassy’s new site as an “off location”, the spokesman said: “I think Vauxhall is a vibrant and important part of London and home to many businesses. Obviously Apple are moving their headquarters there.”

Prime Minister Theresa May met US President Donald Trump in September (Stefan Rousseau/PA)
Prime Minister Theresa May met US President Donald Trump in September (Stefan Rousseau/PA)

The spokesman added: “A state visit (invitation) has been extended and accepted and we will confirm the details in due course.

“No date was confirmed for any visit, the one you are referring to now. The opening of the US embassy is a matter for the US.”

Mr Trump’s announcement followed speculation that he would formally open the embassy at a ceremony in February.

The new building will open for business on January 16.

Mrs May controversially extended the offer of a state visit, officially on behalf of the Queen, when she became the first world leader to meet Mr Trump in the White House following his inauguration last year.

Since then, however, the president has indicated he does not want to take up the invitation if he is going to face mass demonstrations and it had been expected he could make a low-key working visit rather than a trip which involved all the trappings of a state occasion.