Theresa May is facing a full-blown diplomatic standoff with the US after Donald Trump condemned Britain’s “stupid” Washington ambassador over leaked memos critical of the White House, as Downing Street insisted Sir Kim Darroch had its full support.

The escalating crisis began after a Sunday newspaper printed extracts of confidential memos in which Darroch labelled Trump’s administration “inept” and “dysfunctional”. The US president announced on Monday he would no longer deal with the ambassador.

In a fresh volley of tweets on Tuesday morning, Trump again condemned Darroch and renewed his criticism of the prime minister over her Brexit negotiations, which he had praised on his state visit to the UK just over a month ago.

“The wacky ambassador that the UK foisted upon the United States is not someone we are thrilled with, a very stupid guy,” Trump wrote. “He should speak to his country, and Prime Minister May, about their failed Brexit negotiation, and not be upset with my criticism of how badly it was handled.

“I told her how to do that deal, but she went her own foolish way – was unable to get it done. A disaster! I don’t know the ambassador but have been told he is a pompous fool. Tell him the USA now has the best economy and military anywhere in the world, by far and they are both only getting bigger, better and stronger.”

It emerged later that Darroch would not accompany Liam Fox, the international trade secretary, who is in Washington, to the White House for a meeting with Ivanka Trump on Tuesday.

Donald J. Trump

✔

@realDonaldTrump

The wacky Ambassador that the U.K. foisted upon the United States is not someone we are thrilled with, a very stupid guy. He should speak to his country, and Prime Minister May, about their failed Brexit negotiation, and not be upset with my criticism of how badly it was...

The deeply personal condemnation, unprecedented in the recent history of relations between the US and UK, made no apparent impact on Downing Street’s view, with May’s spokesman saying subsequently that Darroch would remain in his post.

“The prime minister’s view is that he is a highly respected and dutiful public servant, and he has the full confidence of the prime minister.”

In a pointed riposte to Trump’s criticisms of May’s Brexit negotiations, the spokesman noted the president’s comments at a joint press conference during his state visit to the UK “in which he said she brought the negotiations to a very good point, and that the PM deserved a lot of credit. And as you know, nothing further has happened in the Brexit negotiations since then.”

The spokesman declined to say why Darroch was not accompanying Fox to the White House, saying the ambassador was “supporting Liam Fox on his trip in other ways”.

It is understood Darroch took the decision himself to avoid putting Ivanka Trump in a difficult position, given the current context.

Darroch has been prevented by Trump from attending a dinner for the Emir of Qatar, but the Foreign Office was reassured this was a one-off, and it does not denote he is being debarred from future events or meetings.

The foreign secretary, Jeremy Hunt, believes the next British ambassador to Washington should be a career diplomat, since to do otherwise would probably be seen to be giving a victory to the leakers. Washington was not named as one of the postings that should be open to outside appointments, Foreign Office sources also pointed out.

The foreign secretary has been in touch with Darroch to offer his personal support, and there has been no discussion of him leaving his post early.

On Tuesday morning, May gave the same message to the weekly meeting of her cabinet, condemning the leak to the Mail on Sunday as “utterly unacceptable”.

Describing May’s words to cabinet, her spokesman said: “The prime minister said that while at the same time the views expressed in the documents are not necessarily the views of ministers or the government, it is hugely important that ambassadors are able to provide honest, unvarnished assessments of the politics in their country. She said it is therefore absolutely right that we continue to give Sir Kim Darroch our full support.”

In his tweets on Monday, Trump said: “I do not know the ambassador, but he is not liked or well thought of within the US. We will no longer deal with him.

“The good news for the wonderful United Kingdom is that they will soon have a new prime minister. While I thoroughly enjoyed the magnificent state visit last month, it was the Queen who I was most impressed with!”

In criticism of May, he wrote: “I have been very critical about the way the UK and Prime Minister Theresa May handled Brexit. What a mess she and her representatives have created. I told her how it should be done, but she decided to go another way.”

The words will be a blow to the outgoing prime minister, who has placed great store in seeking to develop close ties with Trump, visiting him in Washington soon after his inauguration and then agreeing to the state visit, and an earlier working visit, both of which were greeted by protests. (Agency report)

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