Adding to his extraordinary takedown of May, Trump praised Boris Johnson, who stepped down this week as foreign secretary over Brexit. You see what's going on throughout the world with immigration.
Vickers added: "He would be wise not to attempt to kiss her, and I don't expect for a moment that he will".
"We had a dinner where I think we probably never developed a better relationship than last night".
But he noted he was "going to a pretty hot spot, with a lot of resignations right now".
Mr Trump went further and suggested to the Sun Mr Johnson was "a great representative for your country".
Then, in a head-snapping pivot at the end, he declared the alliance a "fine-tuned machine" that had acceded to his demands to speed up increases in military spending to relieve pressure on the United States budget.
The president is expected to avoid areas where major demonstrations are planned in protest at his visit.
The Trumps landed in Air Force One at Stansted Airport at lunchtime on Thursday to kick-start a four-day working visit to Britain as protests against his trip began.
"My message to those coming to the protests in London is that this must be peaceful and good-spirited", he said.
Anti-Trump protesters lined the roadway leading to the palace near Oxford - but it's unlikely the Trumps even saw them. The president claimed Europe is "losing its culture" because of immigration from the Middle East and Africa.
Downing Street insisted Mrs May welcomed Mr Trump's decision to "engage" with the Russian leader.
Such concerns will also dog investors who have been betting the Bank of England will raise interest rates as early as August, following some recent positive signs such as monthly economic growth data and upbeat comments from Governor Mark Carney.
Trump has always been a Brexit supporter and has expressed enthusiasm for a wide-ranging trade deal with Britain after Brexit, something heralded by eurosceptics as being one of the great benefits of exiting the bloc.
Only one person, the digital entrepreneur and philanthropist Baroness Martha Lane-Fox, has publicly refused the invitation.
Mr Trump arrives Thursday afternoon following a North Atlantic Treaty Organisation summit in Brussels and largely avoids the capital's centre and the protesters.
On Friday, Mr Trump will again meet Mrs May at the Royal Military Academy in Sandhurst to watch a military demonstration.
He then travels north to Scotland where he will spend the weekend privately, joined by son Eric Trump.
In an interview published just hours before he was due to have lunch with May and tea with Queen Elizabeth on Friday, Trump chided the "very unfortunate" results of the prime minister's Brexit negotiation.
The Police Commissioner for Lincolnshire later tweeted that "sadly" there were reports officers who put photographs of the "sorry conditions" on social media were being "sought out".
Trump, as he has before, criticized London's mayor, Sadiq Khan, as having "done a very bad job on terrorism". Trump's late mother hailed from Scotland, and he owns two luxury golf courses there.
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