Theresa May reminded President Trump of the number of British and USA workers each country's businesses employed at a black tie dinner in Blenheim Palace as she pressed the case for a post-Brexit trade deal.
Trump, who has compared the June 2016 referendum in which a majority of British voters supported leaving the European Union to his own election that year, accused May of abandoning British voters with her Brexit plans. Trump attended the summit, where he provoked a crisis session to force allies to raise their defence spending.
Perhaps in a reference to Mr Trump's meeting with Vladimir Putin on Monday, she said that Britain and the USA work closely together in the interests of their shared security, "whether through targeting Daesh [Islamic State group] terrorists or standing up to Russian aggression".
"I am going to a few hot spots", he told journalists.
"The United States' commitment to North Atlantic Treaty Organisation remains very strong", Trump told reporters at a surprise news conference following an emergency session of North Atlantic Treaty Organisation members held to address his threats. Frankly, Putin may be the easiest of them all, who would think?
He added: "The deal she is striking is a much different deal than the one the people voted on".
The US Ambassador to London, Woody Johnson, insisted last week that Trump's itinerary was not intentionally designed for him to avoid encountering throngs of protesters.
Earlier today Trump gave an extraordinary press conference in Brussels after giving North Atlantic Treaty Organisation leaders a bruising over defence cash, where he wrote off protesters and said Theresa May's Brexit deal probably wasn't what Britons voted for.
He said he got along with Theresa May "very well", but suggested he might make time during his United Kingdom visit to speak with his friend Boris Johnson, who has just rocked her Government by resigning as foreign secretary.
The 36-year-old, who described Mr Trump's rhetoric as not "entirely to my taste", said she believes he is a proud American nationalist who has generally stuck to the pledges he made to voters.
"This week we have an opportunity to deepen this unique trading relationship and begin discussions about how we will forge a strengthened, ambitious and future-proof trade partnership".
Trump's immigrations views may be applauded in some quarters in Britain, but they have appalled many others. Around 50 percent think the visit should go ahead, compared with 37 percent who think the visit should be canceled.
"I would actually say that she probably went the opposite way". Having to play nice with the person you don't have very much in common with, because it's the right thing to do. And more than 50,000 people have signed up to demonstrate in London on July 13, Reuters reported.
The antipathy between Trump and segments of the British public started during the 2016 presidential campaign, when Trump called for a temporary ban on Muslims entering the United States.
Trump blamed London mayor Sadiq Khan for allowing the protests and blasted the city's first Muslim leader as weak on terror and crime.
Winfield House is the only place where Trump will spend time in central London, where demonstrators are expected to gather in their tens of thousands for a march on Friday afternoon, hours after a giant "Trump baby" balloon is flown near the UK Parliament in an eye-catching stunt.
A campaign is also underway to get "American Idiot", a 2004 song by the US punk rock band Green Day, to the top of the UK Singles Chart.
On Thursday, Trump will travel to Blenheim Palace, the 18th-century stately home where Britain's World War Two leader Winston Churchill was born and spent most of his childhood.
Mrs May and her husband Philip, joined by around 150 guests, waited outside Blenheim Palace in the sunshine for the president and first lady.
He cast doubts on whether the Prime Minister was delivering what the British people had voted for in the European Union referendum.