"It was a harrowing clip, and we wanted to make sure that Donald Trump could hear it", Shabbir Lakha, one of the organizers of the protest, told CBS News. "If they do that, then their trade deal with the USA will probably not be made".
Ahead of the President's first United Kingdom visit, Downing Street was keen to stress the importance of the "special relationship", as the government looks to secure new trade deals ahead of Britain's departure from the EU.
"No, no, no, no". At issue is an interview in the tabloid Sun newspaper in which he was critical of May on Brexit and for not taking his advice (otherwise she'd be better off, he suggested in the interview).
May is facing a rebellion by Brexit hardliners over the proposals, including the resignation of Johnson and Brexit minister David Davis this week, although moderates and big businesses have been supportive. "He's been saying very good things about me as president".
"Now he might not like the current president, but I represent the United States", Trump said.
In the Sun interview, which was conducted during Wednesday's North Atlantic Treaty Organisation summit in Brussels, Trump renewed attacks on Mayor of London Sadiq Khan, with whom he has a long-running feud. Khan, London's first Muslim mayor, has been targeted by the president repeatedly on Twitter.More news: What Trump's tough-guy act at North Atlantic Treaty Organisation was really about
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However, Jacob Rees-Mogg - a leading Conservative Brexiteer and considered a potential alternative party leader by some - said it was perfectly reasonable for Trump to make such comments, adding that May now had an opportunity to change her mind on her Brexit plan.
Organizers blasted audio in the direction of the ambassador's house, which they said was a recording of child migrants who had been separated from their parents while trying to enter the United States.
"So I think allowing millions and millions of people to come into Europe is very, very sad", he said.
This is what White House spokespeople do when a statement they're tasked to deliver is ridiculous and they'd rather attribute it to Trump rather than sacrifice their own credibility.
As his performance at North Atlantic Treaty Organisation showed on Thursday, Mr Trump takes the opposite approach, firing off scatter-gun, apparently off-the-cuff remarks in sometimes rambling responses which can surprise his hosts and his White House staff alike.
"I would actually say she probably went the opposite way", Trump said.
"Look around", he said.
May also wants Trump to pressure Russia's Vladimir Putin, whom he will meet in Finland immediately after leaving Britain, about the Novichok poisonings on English soil in which intelligence agencies believe the Kremlin had a hand.
Calling her a "tremendous woman", Trump said "she has really never made a mistake". You don't see, like, anything embarrassing.