In London, we speak with Sheila Menon, social justice activist and one of the organizers behind the Trump baby blimp.
Americans in London have been warned to "keep a low profile" during the trip, while a crowd-funded "Trump Baby" blimp has been cleared for take-off on Friday morning outside Parliament House.
The US President reached London after attending a North Atlantic Treaty Organisation summit in Brussels, where he said member countries agreed to increase their military spending.
In the busy south London neighborhood of Brixton, Victor Greetham, who runs a jazz bar, said he hasn't been to a demonstration since he protested against the Iraq War in 2003, but he planned to attend one of the protests against Trump's visit.
In the weeks before the American president's inauguration, May sent Trump a copy of the text of Churchill's 1941 Christmas Eve radio address to Americans, delivered while the prime minister was staying with U.S. President Franklin Roosevelt after the attack on Pearl Harbor.
It has been dubbed Storm Trump and the country is braced for a United States presidential visit that has split opinion like never before.
"It's a disastrous and divisive time, and Trump is very much part of that", he said.
"I said "If the President is coming to town I'll call it the Trump Arms", he said.
"From the public, the welcome will be far from warm", he told lawmakers on Wednesday, noting there would be protests across the country against Trump's "abysmal record on human rights, his repugnant attitude towards women and his disgusting treatment of minorities". I think that " s why Brexit happened".
Yet according to David Wemer of the Atlantic Council, a new U.S. -U.K. trade deal isn't a high priority for the Trump administration.
Mr Morgan, the forthright journalist and broadcaster, hit back and questioned why the London mayor had not been so vocal over the visit of controversial Turkish President Recep Erdogan.
May will host a black-tie dinner for Trump there, attended by senior ministers and about 100 business leaders, including from Blackstone group, Blackrock, Diageo, McLaren and Arup.
The president and his wife Melania are due to arrive in Scotland on Friday evening after meeting the Queen at Windsor Castle.