United States President, Donald Trump started his state visit to the United Kingdom on Monday by calling the Mayor of London, Sadiq Khan a stone cold loser who has done a terrible job.

“Khan 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,” Trump wrote on his Twitter account.

“@SadiqKhan, 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 added.

The morning tweets about Khan reiterated comments Trump made just before leaving the US. When asked by reporters if he would be willing to meet with Khan in London, Trump replied: “No, I don’t think much of him. He’s the twin of de Blasio, except shorter.”

Trump’s comments came after Khan wrote an opinion piece in The Observer newspaper on Sunday condemning Trump’s state visit and grouping him together with far-right leaders in Europe.

“It’s so un-British to be rolling out the red carpet this week for a formal state visit for a president whose divisive behaviour flies in the face of the ideals America was founded upon — equality, liberty and religious freedom,” Khan wrote.

“At what point should we stop appeasing and implicitly condoning his far-right policies and views? Where do we draw the line?” Khan, who is the son of a Pakistani bus driver added.

This is not the first time that the Mayor, who is Muslim has criticized Trump. After Trump suggested a ban on Muslims entering in the US during his campaign for president, the then newly-installed Khan said he wanted to ‘educate’ Trump on how to be Muslim and be Western.

Again, just after the June 2017 terror attack in London, Trump criticized Khan, although seemingly misunderstanding the Mayor’s remarks about the attack and calling them a ‘pathetic excuse’. Khan then called for the offer of a state visit to be rescinded.

Trump’s tweets about the mayor also come after he had spent the last few days ‘inserting’ himself into British politics thus breaching the diplomatic custom that heads of state do not meddle in the domestic affairs of the nations they were visiting.

Trump had over the weekend endorsed former London Mayor, Boris Johnson to succeed Theresa May as the British Prime Minister and leader of the Conservative Party.

He also criticized the American-born Duchess of Sussex, the former Meghan Markle, saying that he did not know that she was nasty after he heard comments she made about him during the 2016 campaign.

During the visit, Trump will be treated to a display of British royal pageantry including lunch and a formal state dinner with the Queen, tea with Prince Charles and a tour of Westminster Abbey, the coronation church of English monarchs for nearly a thousand years.