Pound drops sharply on comments from Trump that May's Brexit plans will "probably kill" any US-UK trade deal.
Trump told the newspaper he had advised May on how to conduct Brexit negotiations, "but she didn't listen to me".
Although Trump has said this practice will be stopped, thousands of children remain separated from their parents and face great difficulty locating their relatives.
"I guess when they put out blimps to make me feel unwelcome, no reason for me to go to London", he said.
On Brexit, he said: 'I would have done it much differently.
"I actually told Theresa May how to do (Brexit)", the US leader said in the interview, "but she didn't agree, she didn't listen to me".
The U.S. and United Kingdom have a long history as allies and partners but this visit comes after a tense two-day North Atlantic Treaty Organisation summit, and as the British prime minister deals with her own political crisis as her party struggles to navigate Brexit.
May likewise glossed over the comments in the Sun.
- Kyle Griffin (@kylegriffin1) July 13, 2018 The president added that he has experienced "an incredible two days" in the country, and stressed that he is working with May's government on anti-terror policy and broader U.S.
With its straw-blond hair, questionable face tan and unmistakably out-of-proportion hands, a blimp meant to depict President Donald Trump as a screaming baby flew outside the Parliament building in London Friday.
"When I am asked questions about President Trump I try not to respond and try to be the bigger man".
"She should negotiate the best way she knows how".
Khan, in an interview with NPR's Mary Louise Kelly, says Trump is "entitled to have his views".
"Moral outrage is water off a duck's back to Trump", the group added.
'I think he is a great representative for your country.
The answer, for Trump, was to conduct an interview before he arrived, in this case on the sidelines of the North Atlantic Treaty Organisation summit, at the U.S. embassy in Brussels, with Murdoch's Sun tabloid. Just as the U.S. president's remarks that her plan would "kill" any trade deal with the United States began to reverberate around social media on Thursday evening, the former Ukip leader used an appearance on Andrew Neil's This Week to claim he had fed the idea to Trump.
In the interview, Trump chastised another nemesis - London Mayor Sadiq Khan - accusing him of having done a "very bad job on terrorism".
There are street protests of Trump's first visit to Britain since taking office almost 18 months ago. Margot James, a digital industries minister, tweeted, "No Mr. President Boris Johnson would make a bad prime minister".
"There is no stronger alliance than that of our special relationship with the USA and there will be no alliance more important in the years ahead", the British leader said.
In the Sun interview, which was conducted during Wednesday's North Atlantic Treaty Organisation summit in Brussels, Trump renewed attacks on Mayor of LondonSadiq Khan, with whom he has a long-running feud.
That was just one of several helicopter rides on the agenda for Trump, whose staff opted to keep him largely out of central London and the swarms of demonstrators who are likely to provide some of the defining images of his first official trip to the UK.