Theresa May has said the British ambassador to the US has her "full support", despite Donald Trump saying he would no longer work with him.
The Prime Minister has stood by Sir Kim Darroch, who came under fire after a number of his emails, including one calling the Trump administration "inept", were leaked to a newspaper.
The situation escalated overnight after the US president took to Twitter to say he would "no longer deal" with Sir Kim.
He also took aim at Mrs May, criticising her handling of Brexit.
"What a mess she and her representatives have created," he wrote.
"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!".
WATCH: Tom Tugendhat calls for a police inquiry into the email leak
It comes just a month after the government rolled out the red carpet for the president for a state visit in which he praised the enduring strength of the "special relationship".
In the Commons, there were calls for the police to investigate amid widespread anger at the diplomatic fall-out from the leak.
Tom Tugendhat, chairman of the Commons Foreign Affairs Committee, told MPs he had written to the Metropolitan Police Commissioner Cressida Dick to "ask that a criminal investigation also be opened into the leak".
He told talkRADIO yesterday that the leaking of Sir Kim's memos was an act of "treason".
The Foreign Office, which originally described the leak as "mischievous", launched a formal leak inquiry on Sunday.