Thousands of protesters are expected to join demonstrations during his visit, including plans to fly a blimp over parliament portraying Trump as an angry orange baby.
The U.S. ambassador to the United Kingdom on Wednesday downplayed the hype over a giant balloon depicting a baby President Trump due to float down the streets of London in protest of his visit this week - saying it doesn't reflect the views of the majority of British people. Some plan to stage an "all-night noise protest" outside the barricades surrounding Winfield House later Thursday, with those attending urged to "bring pots, drums and vuvuzelas".
The sad news for Trump Baby is that Trump himself apparently won't be spending much time in London itself and is unlikely to see his inflated, infantile likeness in person.
He is also expected to visit Scotland - where he owns two golf courses - before heading back to the US.
On Friday, Trump will meet May and her newly appointed Foreign Secretary Jeremy Hunt at the prime minister's countryside retreat, Chequers.
- "Biggest insult" - The centrepiece of the organised opposition will be a march through central London ending in a rally on Trafalgar Square.
The US president has angered many in Britain in the last two years with a series of actions and pronouncements. "But I believe the people in the UK, Scotland, Ireland - as you know I have property in Ireland, I have property all over - I think that those people, they like me a lot and they agree with me on immigration".
The prime minister will host Mr Trump and his wife Melania at a lavish dinner at Blenheim Palace on Thursday evening.
Trump pictured setting off to a North Atlantic Treaty Organisation summit in Europe from Joint Base Andrews, Md., on Tuesday.
"It's really kind of irrelevant to what we're trying to do and I don't think certainly it doesn't express the opinion of the British people I met", he said.
Amid reports that the government is working to bring a major police presence to the demonstrations, Amnesty International warned British authorities against attempting to stamp out freedom of expression in an effort to "appease their visitors".