President Donald Trump says the United States and Britain could secure a "great" post-Brexit trade deal, lavishing praise on Prime Minister Theresa May and contradicting his own withering assessment of her strategy publicised hours earlier.
Fresh from sending NATO into crisis talks and ahead of a summit with Kremlin chief Vladimir Putin, Trump shocked Britain's political establishment when he criticised May's plans for ties with the European Union after Britain leaves in March.
Trump and May talk to the media on July 13. Source: AAP
In a newspaper interview published just hours before holding talks with May, Trump said her Brexit strategy would "kill" any chance of a trade deal and said she had not listened to his advice on how to negotiate with the EU.
But, as the two leaders stood together for a press conference, Trump said the British leader was doing a "fantastic job".
Relations had never been more special, he said, and any criticism was "fake news".
"Once the Brexit process is concluded and perhaps the UK has left the EU, I don't know what they're going to do but whatever you do is OK with me, that's your decision," Trump said.
“I would give our relationship with the UK the highest level of special. Am I allowed to go higher than that? I am not sure. It’s the highest level of special. They are very special people, it’s a very special country and as I said, I have a relationship because my mother was born in Scotland.
"Whatever you do is OK with us, just make sure we can trade together ... This is an incredible opportunity for our two countries and we will seize it fully."
Some Conservative lawmakers have cast May's "business-friendly" Brexit plan as a betrayal that would leave Britain too close to the EU and warned that she might face a leadership challenge.
May's formal proposals were published on Thursday, but hours later the Sun published an interview with Trump where he appeared to side with the prime minister's critics.
"If they do a deal like that, we would be dealing with the European Union instead of dealing with the UK, so it will probably kill the deal," he told the Sun. "I would have done it much differently. I actually told Theresa May how to do it, but she didn't listen to me."
Asked about that interview, Trump said he had not criticised May, lavishing praise on "a terrific woman", who was smart, tough and capable.
"This incredible woman right here is doing a fantastic job," he said. "She's a total professional because when I saw her this morning, I said: 'I want to apologise, because I said such good things about you'. She said: 'Don't worry, it's only the press'."
Meanwhile, tens of thousands of protesters marched against the US president through central London, bringing much of the capital to a standstill. It was one of the more than 100 demonstrations planned during his four-day stay.
President Donald Trump and Queen Elizabeth II. The US president says he was not late to their meeting. Source: AAP
The president later travelled to Windsor Castle for tea with Queen Elizabeth. Trump and his wife spent almost an hour with the 92-year-old monarch, staying 17 minutes after their expected departure time.
He later flew to Scotland where he will stay at his Trump Turnberry golf course until Sunday when he heads to Helsinki for talks with Putin, with whom Trump said he would bring up the issue of nuclear disarmament.
