DONALD Trump has intensified his attack on Theresa May’s “foolish” and “disastrous” handling of Brexit while lashing out again at Britain’s ambassador to the US, branding him a “very stupid guy” and “pompous fool”.

As the UK Government carefully seeks to draw a diplomatic veil over a deeply embarrassing episode in the transatlantic Special Relationship, the notoriously thin-skinned US President appears intent on doubling down on his criticisms of the Prime Minister’s handling of Brexit and the analysis of his administration by Sir Kim Darroch, the UK ambassador, who, in leaked emails described it as "dysfunctional" and "inept".

Mr Trump once again took to Twitter to vent his ire.

READ MORE: Theresa May gives ‘full support’ to ambassador after Donald Trump’s war of words 

He wrote: “The wacky Ambassador that the UK 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 handled.

“I told @theresamay 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 & Military anywhere in the World, by far and they are both only getting bigger, better and stronger.....Thank you, Mr. President!”

HeraldScotland: Camley's cartoon: Trump escalates row over diplomat's emails.Camley's cartoon: Trump escalates row over diplomat's emails.

Nicola Sturgeon took to Twitter to give a response. The First Minister posted: "Extraordinary stuff. And huge litmus test for next PM - will he stand up for the ability of diplomats to do their jobs or give in to this kind of behaviour by the US President?"

It was only last month during the presidential state visit that Mr Trump was praising Mrs May’s handling of Brexit, declaring: “The Prime Minister’s brought it to a very good point where something will take place in the not-too-distant future; she’s done a very good job.”

He told their joint press conference: “Perhaps you won’t be given the credit you deserve if they do something but I think you deserve a lot of credit; I really do.”

Asked if Mrs May was bemused by the apparent switch in Mr Trump’s thinking, her spokesman said: “The PM and the President have discussed Brexit on a number of occasions, including most recently during the state visit when both leaders made public remarks about the good deal she had secured.”

Asked if she did not agree with Mr Trump that she had made a mess of Brexit, he replied: “The PM has set out she secured a good deal.”

He refused to discuss the presidential tweets, stressing how Sir Kim had Mrs May’s “full support”.

READ MORE: Jeremy Corbyn calls on new Tory leader to stage second Brexit referendum 

The spokesman confirmed there had been intergovernmental contact between officials last night and today.

Asked if this was the UK Government to apologise, he said it had been made clear to the White House that the leaks were unacceptable.

Given Mr Trump’s remarks that the US administration would no longer deal with Sir Kim and, indeed, the ambassador was said to have been disinvited to a White House dinner last night, the spokesman was asked how he would be able to continue doing his job.

“The ambassador remains in place and continues to carry out his duties with the full support of the PM,” he replied, stressing: “The UK Government determines who its ambassador is.”

Asked if Sir Kim had offered to resign, the spokesman said: “I’m not aware of anything in that regard.”

The issue of the diplomatic row was the first issue on today’s Cabinet agenda.

The PM reiterated to colleagues that the leak was “utterly unacceptable” and an inquiry was underway. She explained how the UK Government had communicated to Washington “how unfortunate” the leak was and that the extracts were selective and did not reflect the closeness of the UK-US relationship.

Mrs May pointed to the recent state visit, emphasising how the two countries had a “deep and enduring” bond based on their long history and shared values.

The spokesman explained that the PM said while Sir Kim’s views expressed in his emails were “not necessarily” those of ministers and the Government, it was extremely important that ambassadors gave honest and unvarnished assessments of the politics of the host country.

“’It is absolutely right that we continue to give Sir Kim Darroch our full support,’” he quoted her as saying.