Britain would leave the EU's single market and customs union as planned, to end free movement of people and sign its own non-EU trade deals.
The Trumps arrived at the grounds on the president's Marine One helicopter and therefore avoided the estimated 1,000 protesters gathered outside.
"The United States' commitment to North Atlantic Treaty Organisation remains very strong", Trump told reporters at a surprise news conference following the emergency session of North Atlantic Treaty Organisation members.
A large balloon depicting the USA president as a giant infant will be allowed to fly over London during the president's four-day visit to the United Kingdom after the capital's Mayor Sadiq Khan gave his permission.
Speaking to BBC Radio 4's Today programme, Mr Ruddy said: 'Trump will think the baby balloon is about him so it's probably a positive thing.
Trump personally criticized May's handling of Brexit, saying that her so-called soft-Brexit approach went "the opposite way" to what he had recommended and that it was "very unfortunate".
Supporters of Donald Trump say a protest baby blimp set to fly over London is disrespectful to the President - but one thinks he will actually find it "funny".
"We must show Trump and the Tories that we can and we will defeat the politics of division".
Mayor of London Sadiq Khan has urged those attending the protests not to cause trouble. Just Say No and No To Trump, No To War.
As Phillips says, on the whole, the US leader may not get the reception in Britain that he had hoped for.
USA will reunite and release over 50 immigrant children
Throughout the reunification process, Sabraw has been strict on the government in his attempts to reunite the families. Of that group, they said, 34 parents had undergone and passed criminal background checks and DNA verification.
May has previously said she does not believe her Brexit plans should rule out a trade deal with the United States.
"The people voted to break it up so I would imagine that's what they would do, but maybe they're taking a different route, I don't know if that is what they voted for".
Addressing Mr Trump in front of an audience of business leaders at Winston Churchill's birthplace, Mrs May insisted that Brexit provides an opportunity for an "unprecedented" agreement to boost jobs and growth.
"But instead the Tories are rewarding President Trump with a red carpet welcome".
May's "business-friendly" Brexit plan - which would keep Britain in a free trade zone for goods with the European Union but mean it has to share some European Union rules - was agreed by her cabinet only last Friday after two years of wrangling since Britons voted to leave the bloc in a 2016 referendum.
The interview posted online as Prime Minister May welcomed President Trump and the first lady at Blenheim Palace for a lavish gala dinner.
Trump had earlier shrugged off the organised demonstrations, which on Friday will include a giant baby-shaped balloon bearing Trump's features and have required police to be mobilised from across the country.
In a separate endeavor, an artist created a 650-foot crop circle reading, "Fuck Trump" in Russian, on farmland that the president was expected to fly over on Friday.
As well as in London, protests are expected to take place in Bristol, Newcastle, Leeds, Cambridge and Cardiff after Trump arrives here on Thursday.
The Trumps will then head to Windsor Castle for an audience with Queen Elizabeth II over tea before they leave for Scotland for the private leg of their tour.
He will spend the weekend with wife Melania in Scotland, where he owns two luxury golf courses.