President Donald Trump and first lady Melania Trump leave Winfield House, residence of the U.S. Ambassador, before boarding Marine One helicopter for the flight to nearby Blenheim Palace, Thursday, July 12, 2018, in London.
Trump also said Europe is "losing its culture" because of immigration from the Middle East and Africa.
"I think it's a travesty of British values".
While he stressed he did not want to get involved in the UK's internal affairs, he added: "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".
Trump is scheduled to meet with The Queen and British Prime Minister Theresa May.
A YouGov/ITV Tonight poll released on Thursday found there is "broad support" for Trump among Britons.
"He's fundamentally damaging the culture, the discourse, the rules, the laws", said Calah Singleton, a 28-year-old writer who turned out in London.
George Clooney injured in bike accident
Clooney was travelling towards the set in Costa Corallina when a vehicle suddenly turned and struck him, according to La Nuova . Authorities say that Clooney was not seriously injured and confirm he was released from the hospital a short time later.
"And I believe it", the president said past year of the welcome he was shown by China's President Xi.
Meanwhile Amnesty International unveiled a 15-metre banner on Vauxhall bridge opposite the US Embassy branding him a "Human Rights Nightmare".
Trump's visit comes amid fierce protests against the US leader, which includes a blimp portraying him as a big baby.
Despite a series of diplomatic spats between Britain and Trump, May is hoping for a quick trade deal with the USA after it leaves the EU. "I think he is a great representative for your country".
"It's also an opportunity to tear down the bureaucratic barriers that frustrate business leaders on both sides of the Atlantic".
Contrary to President Donald Trump's claim on Thursday that "they like me a lot in the United Kingdom", he was immediately met with angry and rowdy protesters as he arrived in London to meet with Prime Minister Theresa May ahead of larger demonstrations against the president expected to draw tens, if not hundreds, of thousands into the streets nationwide on Friday. Trump is also arriving following a chaotic North Atlantic Treaty Organisation summit.
The Commander in Chief is due to travel north of the border on Friday to spend the weekend playing golf at his Turnberry resort in South Ayrshire.
Trump has frequently angered British politicians. Tens of thousands, or more, are expected to participate.