Britain has had a sharp lesson in dealing with U.S. President Donald Trump's appetite for disruption.
The British pound fell, then rallied, and U.K. politicians reeled, then steadied as Trump showered praise on Prime Minister Theresa May on Friday — hours after an interview in which he criticized her, praised a rival and gave her hard-won Brexit roadmap a battering.
Trump threw his first visit to Britain as president into disarray with an interview in The Sun newspaper in which he said May had ignored his suggestions for negotiating Britain's departure from the European Union and likely "killed" a trans-Atlantic trade deal. He also said May's nemesis, Boris Johnson, who quit the government this week over Brexit differences, would make "a great prime minister."
Yet by Friday afternoon, Trump and May were fast friends. Trump labeled the U.S.-U.K. relationship "the highest level of special" and said May was an "incredible woman" doing a great job.
But his earlier attack shocked many politicians in Britain, where the most vicious differences are often masked by formal politeness.
In one of the milder responses, Universities Minister Sam Gyimah tweeted: "Where are your manners, Mr. President?"
Even May's political opponents rallied to her defense. Opposition Labour Party leader Jeremy Corbyn said Trump should have kept his nose out of British politics.
"It's a very strange thing to do, to come on a visit to another country, to meet that country's prime minister, and then announce that you would like to see as her successor a person who's just resigned from her government," he said.
Trump's Brexit broadside came as May was trying to shift stalled divorce negotiations with the EU into higher gear. Britain will leave the bloc in March, but the two sides have not yet agreed on what sort of relationship they will have after that.
On Thursday, as Trump flew into Britain, May's government published a plan that includes free trade in goods and a common trade rule book with the EU.
Trump told The Sun that such a deal "will probably kill" any prospect of a U.S.-U.K. free-trade agreement. Boosting trans-Atlantic trade ties and paving the way for a post-Brexit deal was one of Britain's main goals for Trump's visit.
The pound fell 0.6 percent to $1.31 after Trump's comments. Connor Campbell, an analyst at SpreadEx, said Trump's remark about a trade deal "undermines the prime minister at the end of an already challenging week."
But after talks with May at her Chequers country retreat over a lunch of Dover sole, Chiltern lamb and lemon meringue pie, Trump said he thought a post-Brexit trade deal would be possible.
"The only thing I ask of Theresa is that we make sure we can trade and we don't have any restrictions because we want to trade with the U.K. and the U.K. wants to trade with us," he said.
Sterling rose to over $1.32 after the remarks.
Trump's interview had threatened to weaken May's already fragile hold on power. Her Conservative government is deeply split between supporters of a clean break with the EU and those who want to keep close ties with the bloc, Britain's biggest trading partner.
Brexit Secretary David Davis and Johnson, the former foreign secretary, both quit this week to protest May's trade plan. Johnson, who helped lead the campaign to take Britain out of the EU, accused May of killing "the Brexit dream."
In his interview, Trump praised Johnson — another unpredictable, talkative populist with a distinctive mop of hair.
On Friday he repeated his opinion that Johnson "would be a great prime minister" — but added that May was doing "a fantastic job," too.
The bonhomie could not mask strong differences between Trump and politicians in Britain, from both government and opposition parties.
In the Sun interview, Trump renewed his attack on London's Mayor Sadiq Khan. The two politicians have clashed on Twitter over Trump's ban on immigrants from several mostly Muslim countries and on the president's views on crime and terrorism in Britain.
Khan's office also gave permission for London protesters to fly a 20-foot (6-meter) balloon depicting the U.S. president as a screaming baby near Parliament on Friday.
Trump claimed that London's first Muslim mayor "has done a very bad job on terrorism" and said Khan "has not been very hospitable" to him.
Tens of thousands of people marched in London Friday to protest Trump's visit. Many condemned Trump's anti-immigration statements and policies.
At a news conference with May, Trump repeated his belief that immigration had been "very bad for Europe" and for the United States.
May declined to agree, saying that "over the years, overall, immigration has been good for the U.K."
But in general all was friendly, the calm after the storm, as the two leaders faced reporters in the sun outside Chequers. Trump and his wife, Melania, then flew to Windsor Castle for tea with Queen Elizabeth II before traveling to a Trump golf resort in Scotland for the weekend.
"I have a lot of respect for the prime minister," Trump said. "I would much rather have her as my friend than my enemy, I can tell you."
Chimed May: "And we are friends."