President Trump was today met with an 82-gun salute as he touched down at Buckingham Palace to meet the Queen for his historic state visit.
The President was greeted with full pomp and ceremony when his helicopter landed on the lawn this afternoon for the official start of his three-day tour.
Prince Charles and Camilla greeted President Trump and his wife Melania at Her Majesty's official residence in London.
They then led the First Couple across the lawn of the palace garden to where the Queen was waiting for them.
The two heads of state will share lunch at the palace before President Trump starts a series of engagements with senior royals.
He landed at Stansted this morning at around 9 a.m. for a three-day trip, having already humiliated outgoing Prime Minister Theresa May over Brexit.
Ahead of his landing, he began tweeting insults at London Mayor Sadiq Khan, calling him a "stone cold loser" and urging him to "focus on crime in London, not me".
He added: "Kahn (sic) reminds me very much of our very dumb and incompetent Mayor of NYC, de Blasio, who has also done a terrible job - only half his height.
"In any event, I look forward to being a great friend to the United Kingdom and am looking very much forward to my visit. Landing now!"
On the morning of his historic visit where he will meet the Queen, PM and other senior Royals:
The President had a long chat with Foreign Secretary Jeremy Hunt on the tarmac, just days after he said he "liked" the Tory leadership hopeful
A body language expert revealed the pair were "like two equals doing business"
The US President and Melania have now flown to the US ambassador's residence at Winfield House ahead of a ceremonial welcome at Buckingham Palace, meeting the Queen for lunch, and a tour of Westminster Abbey
President Trump was greeted with a military welcome from the Royal Air Force - giving them a salute as he walked past.
He then reached out for wife Melania's hand as he guided her away from Air Force One.
Hunt said after the pair talked: "I said to him that we're going to put on a great show for him, because America is our greatest ally."
And he added: "He didn't exactly say he was going to be inviting Sadiq Khan for the Royal treatment at the White House anytime soon."
Also waiting for him as he got off the plane were US ambassador Woody Johnson, the Lord-Lieutenant of Essex Jennifer Tolhurst, representing the Queen, and senior police officers.
He will meet the Queen, Prince Charles, Camilla and Prince Harry later, and take a trip to the Grave of the Unknown Warrior ahead of a lavish state banquet.
Meghan Markle will stay at home with baby Archie in Windsor.
Before even boarding Air Force One back in the US, Trump praised Boris Johnson and Nigel Farage and suggested he may meet them both.
But when asked whether he would be meeting Khan, Trump couldn’t resist hitting out again at his long-time critic.
“No, I don’t think much of him," Trump replied. "I think he’s, he’s the twin of [Bill] de Blasio, except shorter.”
Like 5ft 6in Khan, New York City Mayor Bill de Blasio has a hate-hate relationship with the president.
A spokesperson for the Mayor said this morning: "This is much more serious than childish insults which should be beneath the President of the United States."
They also said he was an example of a "growing far-right threat around the globe".
Trump’s takedown comes after Khan compared Trump's language to that of a "20th century fascist" in an outrageous outburst on the eve of the US President's state visit to the UK.
The mayor labeled the decision to roll out the red carpet for Trump as "un-British" - and criticized the American leader for backing Boris Johnson as the next PM.
The piece in The Observer is just the latest blow in a war of words between Khan and Trump that has included a baby blimp and Twitter wars.
In the searing piece, Khan wrote: "Donald Trump is just one of the most egregious examples of a growing global threat.
"The far right is on the rise around the world, threatening our hard-won rights and freedoms and the values that have defined our liberal, democratic societies for more than seventy years."