BBC diplomatic correspondent James Robbins described the trip as "the most controversial visit ever made by an American president to Britain".
President Trump lands in London on Thursday night for a dinner in his honour at Blenheim Palace in Oxfordshire.
He arrives about a year and a half after Prime Minister Theresa May invited him for a state visit, an invitation that was met intense opposition in the United Kingdom - nearly 2 million people signed a petition to rescind the invite.
Temporary signs indicate road closures around the USA ambassador's residence, where special fences have been erected prior to the US presidential visit at the end of the week, in Regent's Park in London, Britain, July 10, 2018.
The president and first lady will then travel to Windsor to meet the Queen on Friday afternoon.
Police chiefs have warned the massive deployment will have an impact for months, as officers take days off for Trump-related overtime and potentially cause difficulty for colleagues left behind.
"It's a disastrous and divisive time, and Trump is very much part of that", he said. For example, on a working visit, the visiting head of state does not address Parliament, nor is their accommodation organised and funded by the UK.
Top it off with the introduction of trade policies that have targeted some European industries - even though European nations are longtime friends accustomed to easy trade with the United States - and it is not surprising that Trump's itinerary will keep him out of central London on Friday, when large protests are planned.
Thousands of people are expected to protest against the president's visit across the UK. A giant inflatable depiction of Trump as a almost naked baby will hover above Parliament Square. The Home Office said they can be "recompensed by the hosting force".
The Treasury has confirmed it will fund policing costs of up to £5m in Scotland.
"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.
However, despite the welcome from May, many Britons remain deeply opposed to Trump's visit.
In a frank exchange with Piers Morgan on Good Morning Britain, Mr Khan said: "My views are irrelevant".
Following the departure of senior figures, including foreign minister Boris Johnson and Brexit minister David Davis, the political atmosphere is febrile.
"The Mayor of London gave the permission [for the blimp to fly] and, you know, it's disgusting and it should never have happened", he said.