Tump insults Sadiq Khan, calls him 'the twin of de Blasio except shorter'

US PRESIDENT Donald Trump mocked London mayor Sadiq Khan's height moments before jetting off to the UK for a state visit.

Asked on Sunday (2) if he would be willing to meet Khan during his state visit, Trump, whose war of words with the London mayor shows no sign of ending,  said: "No, I don't think much of him. I think that he's a - he's the twin of (New York City mayor Bill) de Blasio, except shorter."

This comes after Khan described Trump as "just one of the most egregious examples of a growing global threat" and compared the language he had used to that of the "fascists of the 20th century".

The London mayor also condemned the UK's decision to roll out the red carpet for Trump.

"This is a man who also tried to exploit Londoners' fears following a horrific terrorist attack on our city, amplified the tweets of a British far-right racist group, denounced as fake news the robust scientific evidence warning of the dangers of climate change.

"And is now trying to interfere shamelessly in the Conservative party leadership race by backing Boris Johnson because he believes it would enable him to gain an ally in Number 10 for his divisive agenda."

During an interaction with reporters, Trump called Johnson a "friend" and said she shared good relationship with Nigel Farage as well.

"Well, I think I may meet with him. He's been a friend of mine. He's been very nice. I have a very good relationship with him," the president said of Johnson.

He went on: "I have a very good relationship with Nigel Farage, with many people over there (in the UK) and we'll see what happens. I may meet with him. They want to meet. We'll see what happens."

Widespread protests will greet Trump during his three-day visit to the UK, with the Trump baby blimp set to fly over London on Tuesday. A giant talking robot Trump sitting on a gold toilet will also be included in this year's protests.

The toilet-sitting Trump prop is 16 feet tall and it will says well-known phrases like "stable genius" and "no collusion" while making fart noises.