After confirming he intends to visit London during his state visit in September, Trump said: “I’m not a fan of your Mayor.

“I think he’s done a terrible job, the Mayor of London. He’s a nasty person.”

As Trump prepared to give Khan two-barrels, the Prime Minister interjected: “He’s actually a friend of mine.”

Dismissing Starmer, Trump continued: “No, I think he’s done a terrible job but I would certainly visit London.”

Hitting back at the President, Khan argued that “diversity makes us stronger, not weaker”.

A spokesman for the London Mayor added: “Sadiq is delighted that President Trump wants to come to the greatest city in the world.

“He’d see how our diversity makes us stronger, not weaker; richer, not poorer.

“Perhaps these are the reasons why a record number of Americans have applied for British citizenship under his presidency.”

Trump’s feud with Khan dates back to before the 47th President won the 2016 US Presidential Election.

Khan had blasted the property-tycoon-turned-politician over his proposed travel ban on Muslims in 2015, labelling the suggestion as “outrageous”.

Trump and Khan continued to lock horns on social media throughout his first stint in the Oval Office, with the London Mayor calling on Theresa May to cancel the President’s first state visit in 2017.

“I don’t think we should roll out the red carpet to the President of the USA in the circumstances where his policies go against everything we stand for,” Khan said.

The London Mayor soon after gave permission to anti-Trump activists to fly a protest blimp of the President.

The blimp depicted Trump, who blasted Khan following the 2017 London terror attack, as a crying baby wearing a nappy.

Trump and Starmer clashed on Khan during a lengthy press conference with journalists at the 47th President’s Turnberry golf resort.

At the start of the pair’s televised discussion, Trump confronted Starmer over the Prime Minister’s pursuit of net zero.

Trump said: “We’re going up to your oil capital in a little while, we’re going up to Aberdeen.

“That’s called the oil capital of Europe and that’s a great asset that you have someday, if they ever think they’ll change their thinking on that.

“You have a great and valuable asset, there’s a lot of valuable resources underground there but that’s a decision for you to make.

“But it’s a very amazing place and it is considered the oil capital of Europe.”

During Trump’s four-day visit to Scotland, the US President also met with European Commission President Ursula von der Leyen.

After the pair unveiled a package to reduce US tariffs on the bloc to 15 per cent, member states were left divided on whether the deal provides a boost to Europe.

While Trump hailed the agreement as the “biggest deal ever made”, Ireland joined a growing number of member states to openly admit it is “not exactly celebrating” the accord.