The Mayor of London, Sadiq Khan, compared Donald Trump to a young child after the US President called him a "stone-cold loser."

Khan told CNN that he was “not offended in the slightest” by the remarks, delivered as Trump began his state visit to the UK on Monday, but added that the US was expected to behave more like a role model.

This is the sort of behaviour I would expect from an 11-year-old.

“This is the sort of behavior I would expect from an 11-year-old,” Khan said. "But it's for him to decide how he behaves. It's not for me to respond in a like manner. I think it's beneath me to do childish tweets and name-calling.”

The president received a royal welcome from Queen Elizabeth on Monday, completed with a guard of honor march, gun salutes and opulent white- tie state banquet at Buckingham Palace.

But the visit has also attracted anti-Trump protests. As Khan spoke to CNN at City Hall in London, a large inflatable caricature of the US President as a diaper-wearing baby was inflated outside the UK Parliament.

Khan said people in London had the right to protest, as long as it's done peacefully. "They'll be articulating the concerns we have about the values we both hold dear," Khan said.

Asked whether the UK should be pragmatic in its approach to Trump, given its desire for a post-Brexit trade deal, Khan warned against false hopes. "His mood changes from hour to hour," Khan said.

“He can be upset by an article in a Sunday newspaper to the effect that he resorts to name-calling.”

The state banquet had a few hundred guests, including several of Trump's children.

The President signed the guestbook at Westminster Abbey. "Thank you so much," his message said. "This has been a great honor. Special place."

In the interview, Khan said Trump had amplified hard-right views and defended white supremacists. "I think it's wrong to amplify the tweets form racists in this country as Donald Trump has done so. I think it wrong, by the way, to separate children from their parents on the border. I think it's wrong to ban people from coming to your country because of the faith they belong to. I think it's wrong to roll back the progress that's been made on the reproductive rights of women or LGBT+ rights."

But the mayor also struck more emollient tone, saying that people in the UK “cherish the special relationship” with the US, “love America and also respect American politicians.”

Khan has long been a critic of Trump. In a Sunday newspaper article, he called the US president a “growing global threat” and said it was “un-British” to be rolling out the red carpet for him.

Trump struck back just moments before touching down in the UK on Air Force One. He tweeted that Khan “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,” Trump tweeted.

Trump repeated his criticism of Khan at a joint press conference with Prime Minister Theresa May later on Tuesday.

Asked for his opinion of the British opposition leader Jeremy Corbyn, Trump appeared to misunderstand the question and started talking about Khan, describing him as "negative."

“He's a negative force, not a positive force," Trump said. "I think he should focus on his job," he added. (CNN)

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