POLICE have been urged to investigate the leak of sensitive diplomatic messages which showed the UK’s ambassador to Washington believed Donald Trump’s administration to be “inept”, as the president escalated the diplomatic dispute.

Downing Street said Theresa May has “full faith” in Kim Darroch after the extraordinary breach of confidentiality triggered a political firestorm on both sides of the Atlantic.

President Donald Trump yesterday said he will “no longer deal” with Darroch and criticised Prime Minister Theresa May for making a “mess” of Brexit, he said on Twitter.

Conservative 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”.

And Foreign Office minister Alan Duncan said police could be involved if evidence of wrongdoing over the leak is found, telling the Commons: “If evidence of criminality is found, then yes, the police could be involved.” While showing support for the ambassador and the need for “unvarnished assessments” of foreign political situations, Number 10 distanced itself from Kim’s withering assessment of the Trump White House. May’s official spokesman told a Westminster briefing on Monday morning: “The PM has full faith in her ambassador to Washington.

“Our ambassadors provide honest, unvarnished assessments of politics in their country, those views are not necessarily the views of ministers or indeed of the Government.

“As the Foreign Secretary has said, this leak is not acceptable.

“We would expect such advice to be handled in the correct way and a leak inquiry has been launched.”

Simon McDonald, Permanent Secretary at the Foreign and Commonwealth Office, told the Public Accounts Committee that “significant damage” had been caused by the leak.

Asked if May agreed with the contents of Kim’s leaked assessment of the Trump administration, the spokesman said: “The PM does not agree with that assessment.”

Trump tweeted: “I have been very critical about the way the U.K. 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. I do not know the Ambassador, but he is not liked or well thought of within the U.S. 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.”

Earlier, International Trade Secretary Liam Fox called for the law to be involved in how the explosive and supposedly secret remarks from the British ambassador to the US became public. Fox said the leaks could damage the UK’s relationship with Washington after Trump made clear his displeasure with Britain’s chief envoy to the US.

Trump hit out at the UK’s ambassador to Washington after the leak of sensitive diplomatic messages painting an unflattering assessment of his administration. The president said Kim had “not served the UK well” and his administration were “not big fans” of the envoy.

Fox, who is visiting the US, told the BBC: “This is such a damaging, potentially damaging, event that I hope the full force of our internal discipline, or even the law, will come down on whoever actually carried out this particular act.”

A formal investigation will be carried out to determine how the candid and highly embarrassing messages from Kim to the UK Government were leaked.

Trump, who was described as “radiating insecurity” in Kim’s assessment, was clearly annoyed by the leak.

He said: “The ambassador has not served the UK well, I can tell you that. We are not big fans of that man and he has not served the UK well. So I can understand it and I can say things about him but I won’t bother.”

Foreign Secretary Jeremy Hunt said he did not agree with all the views expressed by Kim and insisted Britain has the “warmest” of relationships with the US.

Speaking at a press conference at the Foreign Office, Hunt said: “It’s a personal view and there will be many people in this building who don’t agree with that view and indeed I don’t agree with some of the views that we saw in those letters.

“I think the US administration is highly effective and we have the warmest of relationships and a partnership based on standing up for shared values.”