Shortly before landing, Donald Trump tweeted a typically aggressive broadside against London mayor Sadiq Khan -- and it appears Khan was still on his mind as he stepped off the plane moments later.

Trump shared his "very strong views" about Khan with British Foreign Secretary Jeremy Hunt while the pair met on the tarmac, Hunt told the BBC.

"He mentioned to me some of his feelings about the Mayor of London, which I saw subsequently he just tweeted out as well," Hunt said.

Trump had tweeted minutes before landing that Khan was a "stone cold loser," before mocking Khan's height and comparing him to New York's mayor Bill de Blasio, who Trump called "very dumb and incompetent."

Responding to Trump's Twitter comments, a spokesperson for Khan said the President should not be hurling "childish insults" at the mayor: "This is much more serious than childish insults which should be 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," his spokesperson said, according to Britain's Press Association news agency.

According to Daily Mail, Donald and Melania Trump left Washington for the UK on Sunday night and landed at Stansted at 9am.

Prince Harry will meet Trump and Melania - but Meghan Markle will stay away looking after baby Archie

Tonight Her Majesty will host a State Banquet in his honour - but mass protests will be taking place outside

London Mayor Sadiq Khan compared Trump to '20th century fascists' in a column Trump called 'nasty'

The US President is in the UK for three days where the Queen will throw a state banquet at Buckingham Palace in his honour tonight after he meets Her Majesty and Prince Harry for lunch and Prince Charles and his wife Camilla for tea.

Prince Harry will also attend a private lunch at the palace - although his wife Meghan Markle, who is on maternity leave, will be at home with their four-week-old son, Archie.

Trump had already weighed in on Brexit and his security concerns over Huawei as he took off from America last night and used his arrival in the UK to vent his fury over Mr Khan's description of him as a '21st century fascist'.

The US President and First Lady Melania will first head to Buckingham Palace for lunch with the Queen - and will return this evening for the state banquet, which is being boycotted by Labour leader Jeremy Corbyn. In between they will visit Westminster Abbey and also go for tea with Prince Charles at Clarence House.

Courtesy: Daily Mirror/ CNN