US President Donald Trump has been the butt of ridicule often and has always retorted in his characteristic acerbic manner but this time it came from the UK ambassador, envoy of a nation with close ties with US, whose confidential mails to his government were leaked to a newspaper.

British Ambassador to US, Kim Darroch, described the US president and his White House as ‘inept’ and ‘dysfunctional’ and Trump himself as ‘radiating insecurity’.

Reacting, Trump told reporters in the US: “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.”

The UK has meanwhile launched as inquiry into the leak.

Troves of diplomatic cables sent to London by British Ambassador to US Kim Darroch, which contain stinging remarks about US President Donald Trump’s temperament and policies, were leaked to the Daily Mail, which first reported the scoop on Sunday.

The oldest files go back to 2017 and the most recent ones were penned just last month, including a dispatch from June, 22, in which Darroch shares uncensored insight into the erratic policies his country’s top ally is pursuing in regards to Iran.

Darroch had said Trump’s presidency could “crash and burn” and “end in disgrace”, according to a cache of secret cables and briefing notes sent back to Britain seen by the Mail on Sunday newspaper.

In memos to the British government which date from 2017 to the present, Kim Darroch said Trump “radiates insecurity” and advises officials in London that to deal with him effectively “you need to make your points simple, even blunt”.

“We don’t really believe this Administration is going to become substantially more normal; less dysfunctional; less unpredictable; less faction riven; less diplomatically clumsy and inept,” Darroch wrote in one, according to the newspaper.

In others, the newspaper said he had described the administration as “uniquely dysfunctional” and that the “vicious infighting and chaos” inside the White House — widely reported in the US but dismissed by Trump as “fake news” — was “mostly true”.

The paper said the most damning comments by Darroch described Trump, who was received by Queen Elizabeth II during a state visit to Britain just last month, as “insecure” and “incompetent”.

A memo sent following the controversial visit said the president and his team had been “dazzled” by the visit but warned Britain might not remain “flavour of the month” because “this is still the land of America First”.

Although the Mueller investigation later found allegations of conspiracy between the Trump campaign and Russia were not proven, Darroch’s emails said “the worst cannot be ruled out”

In one of the most recent reported dispatches filed on June 22, Darroch criticised Trump’s fraught foreign policy on Iran, which has prompted fears in global capitals of a military conflict, as “incoherent” and “chaotic”.

He allegedly said the President’s assertion that he called off retaliatory missile strikes against the Iranian regime after a US drone was shot down because it risked killing 150 Iranians, “doesn’t stand up”.

“It’s more likely that he was never fully on board and that he was worried about how this apparent reversal of his 2016 campaign promises would look come 2020,” Darroch reportedly stated, referring to the next presidential election.

He added that Trump could still trigger a conflict with Iran. “Just one more Iranian attack somewhere in the region could trigger yet another Trump U-turn. Moreover, the loss of a single American life would probably make a critical difference.”

Darroch wrote that “we could also be at the beginning of a downward spiral, rather than just a rollercoaster: something could emerge that leads to disgrace and downfall.”

But he also warned British officials not to write Trump off, saying there was a “credible path” to him winning a second term in office. He said Trump may “emerge from the flames, battered but intact, like (Arnold) Schwarzenegger in the final scenes of The Terminator.”

While describing the rhetoric Trump uses to fire up crowds at his campaign rallies as “incendiary,” and “a mix of fact and fiction,” the diplomat at the same time marvels at the zeal with which Trump supporters continue to stand by their candidate, comparing the atmosphere of a MAGA rally to a “mega-church” or a “major sporting event.”

The UK foreign ministry said it would carry out a formal investigation into the leak.

British foreign minister Jeremy Hunt distanced himself from Darroch’s remarks, saying: “It’s really important to say that the ambassador was doing his job as an ambassador which is to give frank reports and personal opinions about what’s happening in the country where he works, and that’s his job to send back those reports but they are personal opinions, not the opinions of the British Government, not my opinion.

“And we continue to think that under President Trump the United States administration is both highly effective and the best possible friend of Britain on the international stage.”

Britain’s Foreign Office did not dispute the veracity of the memos. .

“The British public would expect our ambassadors to provide ministers with an honest, unvarnished assessment of the politics in their country,” a spokeswoman said.

“Their views are not necessarily the views of ministers or indeed the government. But we pay them to be candid,” she added.

“Our team in Washington have strong relations with the White House and no doubt that these will withstand such mischievous behaviour,” the spokeswoman said of the potential fallout from the leak.

The Foreign Office later said a formal investigation into the leak would take place.

Darroch is one of Britain’s most experienced diplomats whose posting in Washington began in January, 2016, before Trump winning the presidency.