By Jeff Mason
WINDSOR CASTLE, England (Reuters) - President Donald Trump said on Friday 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 publicized 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 criticized May's plans for ties with the European Union after Britain leaves in March.
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 in the garden of May's grand 16th-Century official residence Chequers, Trump said the British leader was doing a "fantastic job", added it was up to her how to conduct Brexit, and that a free trade deal was very much on the table.
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.
"Whatever you do is OK with us, just make sure we can trade together, that's all that matters. The United States looks forward to finalizing a great bilateral trade agreement with the United Kingdom. This is an incredible opportunity for our two countries and we will seize it fully."
At the same location a week ago, May finally won agreement for her Brexit plans from her cabinet after two years of tortuous internal wrangling. But within days, two senior ministers had quit, departures which Trump said earlier in the week had left Britain in turmoil.
Some lawmakers in her deeply divided Conservative Party 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 criticized May, lavishing praise on "a terrific woman", who was smart, tough and capable.
"This incredible woman right here is doing a fantastic job, a great job," he said. "She's a total professional because when I saw her this morning, I said: 'I want to apologize, because I said such good things about you'. She said: 'Don't worry, it's only the press'."
"HIGHEST LEVEL OF SPECIAL"
May, likewise, glossed over the comments in the Sun, saying her deal provided a platform for an ambitious free trade deal.
Trump's remarks to the Sun were the most biting any U.S. president has ever made on visit to Britain. However, under the blue skies of the Chequers' garden, he said their relationship was "the highest level of special".
However, while Trump and May exchanged warm words, tens of thousands of protesters marched against the U.S. president through central London, bringing much of the British capital to a standstill. It was one of the more than 100 demonstrations planned across the country during his four-day stay.
"The message we came here to give today is that Trump is not welcome in Britain," said shopkeeper Grish Gregoran, 58, who took the day off to attend. "We wanted to embarrass him and I think we have done that today.
Trump has also frequently angered British politicians and has been involved in social media spats with London's Muslim mayor Sadiq Khan who he said had "done a very bad job on terrorism".
Late last year, May herself criticized Trump for retweeting a message by a member of a British far-right group, and the speaker of parliament has said the president would not be welcome to address the chamber.
After leaving Chequers, Trump traveled to Windsor Castle to have tea with Queen Elizabeth. He was heralded by military bands on his arrival at the 92-year-old monarch's home where her grandson Prince Harry married U.S. actress Meghan Markle in May.
He was due to fly to one of his golf courses in Scotland later on Friday where he will stay until Sunday when he flies to Helsinki for talks with Russia's Putin where he said he would bring up the issue of nuclear disarmament.
However his trip is set to be overshadowed by news that a U.S. federal grand jury has indicted 12 military intelligence officers on charges of hacking the computer networks of 2016 Democratic presidential candidate Hillary Clinton and the Democratic Party.
"We have this stupidity going on, pure stupidity, but it makes it very hard to do something with Russia because, anything you do, it's like: 'Russia, oh he loves Russia'," Trump said at the press conference before news of the indictment.
"I love the United States but I love getting along with Russia and China and other countries."
(Writing by Guy Faulconbridge and Michael Holden; Additional reporting by William James, Kate Holton, Andrew MacAskill and Paul Sandle; editing by Larry King, Kevin Liffey, David Stamp, William Maclean)