"It appears that President Trump got the message from the many Londoners who love and admire America and Americans but find his policies and actions the polar opposite of our city's values of inclusion, diversity, and tolerance", mayor Khan said in January.
The president will be greeted by Scottish Secretary David Mundell, who has insisted the president's visit will be a chance for the country to "strengthen vital links" with one of its most important allies.
"I would love to say that I think this is going to be a hugely successful visit but I think it's going to be very hard", he said at a pro-Trump gathering in parliament. The president said on Tuesday, "I think they like me a lot in the United Kingdom".
But Trump is unlikely to see many of those who have mobilized to protest against his visit. A spokesperson at the U.S. Embassy in London said there was nothing political about the timing of the alert, that such warnings were routine.
"He's come out of the woodwork now and I've seen it the last few days; there's huge positivity for what we've done here".
As well as in London, protests are expected to take place in Bristol, Newcastle, Leeds, Cambridge and Cardiff after Trump arrives on Thursday.
Mr Trump - whose mother was from the Isle of Lewis - is due to touch down in Scotland on Friday night before spending the weekend at the famous South Ayrshire course, which he bought in 2014.
Trump will depart the North Atlantic Treaty Organisation summit in Brussels on Thursday afternoon local time and head to London for a greeting ceremony.
Shrugging off the plans for mass protests, which will include a giant baby-shaped blimp bearing Trump's features, he said in Brussels: "They like me a lot in the UK".
A police chief has apologised after it was revealed officers securing Mr Trump's visit to the United Kingdom were being forced to sleep in conditions described as an "absolute disgrace".
The antipathy between Mr. Trump and segments of the British public started during the 2016 presidential campaign, when Mr. Trump called for a temporary ban on Muslims entering the United States.
"And if he's having a cup of tea I'll have a pint of stout".
10 Downing Street said she would be meeting with schoolchildren and veterans on Friday, accompanied by Philip May, U.K. Prime Minister Theresa May's husband.
We're more than used to our best sports-stars and celebrities being picked up as "British" in the English media when they're on the rise, and "Irish" when they're underperforming or in trouble.
The two leaders will hold talks the following day at Chequers, the 16th-century manor house which is the prime minister's official country residence.
The trek, coming more than a year and a half into his presidency, does not have the trappings of a state visit.