A formal inquiry will be held into the leak of diplomatic memos which revealed that Britain's ambassador to the US had described Donald Trump as "incompetent", "inept" and "insecure".
In the memos, obtained by the Mail on Sunday, Sir Kim Darroch gives a scathing assessment of the White House, saying it has become "uniquely dysfunctional" under President Trump because of "vicious infighting and chaos", and questions whether it "will ever look competent".
Officials have insisted the relationship with the White House can withstand the "mischievous behaviour" of the leak and defended Sir Kim's candid style.
However, Foreign Secretary Jeremy Hunt has distanced himself from Sir Kim's remarks, saying: "This was a personal view."
He added: "It's not the view of the British government. It's not my view.
"We continue to think that under President Trump the US administration is not just highly effective but the best possible
friend of the United Kingdom on the international stage."
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The memos, which detail Sir Kim's assessments of the Trump administration from 2017 to the present, suggest that in order to communicate with the president "you need to make your points simple, even blunt".
Following Mr Trump's state visit to the UK in June, Sir Kim said that although the president had been "dazzled" by the pomp and ceremony of the trip, his administration would remain self-interested and "this is still the land of America First".
In one of the most recent documents, Sir Kim refers to "incoherent, chaotic" US policy on Iran and questions Mr Trump's publicly stated reason for calling off a retaliatory airstrike against Tehran following the downing of a US drone.
The US and Iran have been at the brink of armed conflict over tensions in the Gulf, and Mr Trump stated that he called off a planned airstrike with minutes to spare because of the potentially high number of casualties.
But Sir Kim said that the explanation "doesn't stand up", and suggested it may have been motivated by Mr Trump's focus on the 2020 re-election campaign and his previous promises not to involve the US in foreign conflicts.
"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," Sir Kim said.
He said it was "unlikely that US policy on Iran is going to become more coherent any time soon" as "this is a divided administration".
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