The Queen has told a state banquet that shared values will continue to unite the UK and the US, on a day that began with the US President tweeting abuse at London's Mayor.
Donald Trump kicked off his state visit to the United Kingdom on the front foot, branding London Mayor Sadiq Khan a "stone cold loser" on Twitter before Air Force One had even touched down.
He and first lady Melania Trump then flew to Buckingham Palace in Marine One, the presidential helicopter, landing on a lawn where they were greeted by Prince Charles and his wife Camilla.
Although hundreds of thousands of people protested against him during a trip last year, Mr Trump said instead of demonstrations, there had been "tremendous crowds of well-wishers".
"Haven't seen any protests yet, but I'm sure the Fake News will be working hard to find them," he said on Twitter.
Outside the palace, a handful of supporters wore "Make America Great Again" hats and "Trump 2020" shirts. A small number of protesters were also present.
The Trumps had lunch with the Queen and were shown around a collection of items with significance for the US.
The Queen showed off her family's golfing memorabilia, a portrait of George Washington and a draft copy of a telegram from George VI to US General Dwight Eisenhower after the D-Day invasion of France.
The Trumps then went to Westminster Abbey, where they laid a wreath at the grave of the Unknown Warrior, before afternoon tea with Prince Charles and his wife, Camilla, at their official home in central London.
The private tea was a rare chance for Prince Charles, the heir to the throne, to talk with Mr Trump in an informal setting without cameras present.
It is not known if Prince Charles and Mr Trump discussed climate change, which the Prince views as a grave threat and Mr Trump sees as a hoax.
'Common values … will continue to unite us'
The first day of the visit ended with an extravagant state dinner at the palace.
"As we look to the future, I am confident that our common values and shared interests will continue to unite us," the Queen said.
"Tonight we celebrate an alliance that has helped to ensure the safety and prosperity of both our peoples for decades, and which I believe will endure for many years to come."
Mr Trump praised the Queen and recounted her contributions to the World War II effort, when she was a mechanic and military truck driver.
"That young mechanic was the future queen — a great, great woman," he said.
"The bond between our nations was forever sealed in that great crusade.
"As we honour our shared victory and heritage, we affirm the common values that will unite us long into the future: freedom, sovereignty, self-determination, the rule of law and reference for the rights given to us by almighty God."
He thanked the Queen for her hospitality and said he and Melania were "profoundly honoured to be your guests for this historic state visit".
'Stone cold loser' Twitter fracas
Minutes before Mr Trump had even landed for his UK visit, the President had begun to make his mark with his tirade at Mr Khan.
The US President and London's Mayor have a history of exchanging barbs on social media after Mr Trump retweeted anti-Muslim videos from a British far-right group in late 2017.
Mr Khan accused the President of promoting a "vile, extremist group" and added his voice to calls for Ms May to cancel Mr Trump's invitation for a state visit.
The London Mayor later gave permission for protesters to fly the "Baby Trump" blimp during Mr Trump's 2018 visit, with a spokesman saying: "The Mayor supports the right to peaceful protest and understands that this can take many different forms."
A spokesperson for Mr Khan said the "childish insults" were "beneath the President of the United States".
"Sadiq is representing the progressive values of London and our country warning that Donald Trump is the most egregious example of a growing far-right threat around the globe, which is putting at risk the basic values that have defined our liberal democracies for more than 70 years," the spokesperson said.
The agenda for Mr Trump's week-long journey is largely ceremonial and includes D-Day commemoration ceremonies on both sides of the English Channel and his first presidential visit to Ireland.
But Mr Trump's visit also comes at a fraught time in British politics, with Theresa May set to styep down as Prime Minister over the country's Brexit turmoil.