US President Donald Trump has called the Ambassador of the United Kingdom to the US “a very stupid guy”.

On Sunday, scathing comments about US President Donald Trump made in leaked diplomatic cables by Britain's ambassador to the US, Kim Darroch, were published in a British newspaper.

In the messages, Darroch called the leader of the free world "inept," "insecure," and "incompetent." He said that Trump's career could "end in disgrace" and even said of alleged collusion with Russia that "the worst cannot be ruled out."

Trump responded on Twitter, lashing out at British officials, and claiming that Darroch was never liked by Trump's team and that: "We will no longer deal with him".

He continued to attack Darroch on Tuesday: "The wacky Ambassador that the UK foisted upon the United States is not someone we are thrilled with, a very stupid guy ... I don't know the Ambassador but have been told he is a pompous fool."