President Trump arrived in the UK this morning for a scheduled three-day state visit - but not before launching a scathing attack on the Mayor of the UK capital of London.

 “Sadiq Khan, who by all accounts has done a terrible job as Mayor of London, has been foolishly ‘nasty’ to the visiting President of the United States, by far the most important ally of the United Kingdom. He is a stone cold loser who should focus on crime in London, not me," he tweeted.

"Kahn 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!”

The rant comes just a day after audio of the Trump referring to Meghan Markle, the Duchess of Sussex as "nasty." Americans have flooded Twitter with apologies to the Brits on behalf of Trump.

A spokesman for Khan issued a statement in response to Trump's offensive tweets: "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 growing far right threat around the globe."

This is Trump's first official state visit to the UK as president. The visit includes a private lunch with the Queen and a state banquet at Buckingham Palace. Trump will also meet current Prime Minister Theresa May at St James's Palace on Tuesday morning for a business breakfast.