This will be Trump's first visit to England as president. Mass protests are expected across Britain, leading police to mobilize to a degree not seen since 2011.
The largest demonstration is expected in central London on Friday where a giant "Trump baby" balloon will fly close to Parliament after being given the go-ahead by Mayor of London Sadiq Khan. "So instead of 1000 tiny balloons, we have ordered a half-size Trump Baby created to be filled with air - he's made from thicker plastic so he's a lot less fragile than the big boy - meaning he can join in the protests and knock about with people in the crowds".
Mr Trump's schedule will largely keep him out of central London and it seems unlikely that the U.S. president will come close enough to Westminster to see the blimp.
Exercise caution if unexpectedly in the vicinity of large gatherings that may become violent.
With Mr Trump set to travel to Scotland on Friday evening after meeting the Queen at Windsor Castle, a rally is planned for Glasgow's George Square.
"Numerous demonstrations are being planned for July 12 to 14, 2018, surrounding the visit of the President of the United States to the United Kingdom", the USA embassy said in the alert on its website.
LONDON, July 11 (Reuters) - Britain on Wednesday geared up for the arrival of Donald Trump just hours after the USA president waded into the Brexit crisis gripping Prime Minister Theresa May's government and portrayed the closest US ally in Europe as a country in turmoil. Over 10,000 citizens signed the petition to let it fly, which the mayor finally agreed to, seeing it as a "peaceful protest".
May's future was thrown into question after two high-level cabinet members -including Foreign Secretary Boris Johnson- resigned amid the growing chaos surrounding Brexit negotiations.
Already his visit has triggered the largest United Kingdom police mobilization since 2011, the Guardian reported.