Later in the evening the President will head to Scotland for the weekend.
Activists inflate a giant balloon depicting US President Donald Trump as an orange baby in north London on July 10, 2018 ahead of a demonstration in London to coincide with the visit of the US president.
However, after Trump announced his run for President, his tweets about Britain increased in frequency and criticism, with the 45th President of the United States criticising everything and everyone from the NHS, Theresa May, Sadiq Khan, UK policing, UK crime, Brexit and Nigel Farage.
But Donald Trump is not just any leader.
At the same time, Trump will be touring a defense site with May outside of London.More news: Parents of rescued boys now at hospital told 'no hugging' yet
May hopes Trump, who arrived at Stansted airport from Brussels, will help accelerate a future free trade deal, though his public comments on Brexit have cast a shadow over the visit.
Nick Hurd, Britain's Policing Minister, told parliament police expected more than 100 protests across the country, including two large demonstrations in London on Friday, and there were robust and proportionate plans in place.
Tens of thousands of people are expected to march through London in protest against Mr Trump's visit and some of his actions during his first 18 months in power.
"Donald Trump could do perfectly fine doing rallies in the USA".
Protests are expected against Trump, whose policies - including a travel ban on a number of predominantly Muslim countries, detention of child migrants on the US-Mexico border and imposition of tariffs on European Union steel and aluminium exports - have all been criticised by the UK.
"Our trade and investment relationship is unrivalled - we are the largest investors in each other's economies and every day a million British people go to work for US companies in the UK and a million Americans go to work for UK companies in the US".More news: Tottenham Hotspur's Harry Kane hoping to inspire next generation by reaching final
"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.
He said: "I recently read a story that in London, which has unbelievably tough gun laws, a once very prestigious hospital right in the middle is like a war zone for frightful stabbing wounds". She's planning to attend anti-Trump protests.
Then, on Friday, he meets the Queen at Windsor Castle before making his way to Scotland for the rest of the visit.
They are scheduled to spend Thursday night at the US Ambassador's home Winfield House, in Regent's Park.
He also said he had "always liked" Boris Johnson, who quit as foreign secretary on Monday, while he joked that his meeting with Russian leader Mr Putin in Helsinki next week "may be the easiest" part of his European trip.More news: England's squad all train ahead of World Cup semi-final against Croatia
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