Donald Trump lashed out at Theresa May on Monday, visibly angry at her continuing support for the British ambassador to Washington despite the leak of diplomatic cables highly critical of his presidency.
London has been scrambling to stem the damage caused by the release of confidential telegrams from envoy Kim Darroch, which described Trump as "inept" and his White House as "uniquely dysfunctional".
In a series of tweets, Trump assailed the British premier, welcoming her impending departure from office, and saying he would have no further contact with the ambassador.
"I have been very critical about the way the UK and Prime Minister Theresa May handled Brexit," Trump wrote. "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 good news for the wonderful United Kingdom is that they will soon have a new Prime Minister," Trump wrote.
Regarding the envoy Darroch, Trump declared: "We will no longer deal with him."
"I do not know the Ambassador, but he is not liked or well thought of within the US," the president said.
The British prime minister's office called the leak "unacceptable" but also defended the work of ambassadors in providing "honest, unvarnished assessments of politics in their country".
"The prime minister has full faith in her ambassador to Washington," a Downing Street spokesperson said.
The release of the cables came just a month after a state visit by Trump that included a 41-gun salute welcome at Buckingham Palace and a banquet dinner with the queen.
"While I thoroughly enjoyed the magnificent State visit last month, it was the Queen who I was most impressed with!" Trump tweeted.