London mayor Sadiq Khan has accused Donald Trump of being racist, sexist and Islamophobic after the US president used a speech to the United Nations to claim sharia law was being embraced in the UK capital.
In his address to the UN General Assembly in New York on Tuesday, Mr Trump claimed illegal immigrants had overrun continental Europe and the United Kingdom, and personally called out Mr Khan.
"I look at London where you have a terrible mayor, a terrible, terrible mayor and it's been so changed, so changed," he said.
"Now they want to go to sharia law, but you're in a different country, you can't do that. Both the immigration and their suicidal energy ideas will be the death of Western Europe if something is not done immediately."
Mr Khan, who has served as the mayor of London since 2016 and is the first Muslim to hold the position, said Mr Trump's remarks spoke to his "Islamophobic" ideologies.
"People are wondering what it is about this Muslim mayor who leads a liberal, multicultural, progressive, successful city that means I appear to be living rent free inside Donald Trump's head," he told the BBC.
"I think when people act in a certain way, when people behave in a certain way, you've got to believe them.
"I think President Trump has shown he is racist, he is sexist, he is misogynistic, he is Islamophobic."
Sharia is the legal system in Islam that guides aspects of many Muslims' lives.
While Britain has many sharia "councils", which cater to the religious needs of some Muslims, they are not part of the British legal system and sharia law does not have any formal state recognition in the UK, a secular country.
'I think President Trump's wrong,' Khan says
Asked what he made of Mr Trump's characterisation of him as a "terrible mayor", Mr Khan touted London's global brand and record US tourism to the city.
"I'm just thankful that we have record numbers of Americans coming to London since records began. There's not been a period when more Americans have come to London," he said.
"We're often the number one city in the globe when it comes to culture, when it comes to foreign investment, when it comes to sports, when it comes to the ability of people to meet their potential."
"I've seen the benefits of Americans coming to London, I've seen the benefits of people recognising what a great city we are."
Mr Khan also said Londoners "expected more" from their politicians when it came to standing up for the city and its interests.
"You should have the confidence to call them out when they're wrong, and I think President Trump's wrong in many many ways."
It comes after Mr Trump's historic state visit to the UK last week, which included a lavish royal banquet and a bilateral meeting with Prime Minister Keir Starmer.
Mr Starmer's Labour government has stopped short of criticising the Trump administration despite differences on issues issues such as Palestinian recognition, as London hopes to serve as a bridge between Europe and Washington.
Trump-Khan feud dates back a decade
This week's exchanges are far from the first time Mr Trump and Mr Khan have come to blows, with the pair exchanging political barbs at various points since 2015.
During Mr Trump's first state visit to the UK in 2019, he referred to the London mayor as a "stone cold loser" hours before dining with Queen Elizabeth II.
In 2017, Mr Khan also blasted Mr Trump's tweets as "ill-informed" after the US president attacked the mayor's response to the London Bridge van attack which left seven people dead and dozens more injured.
Mr Trump also argued the attack was justification for his failed attempts to institute a ban on travellers from Muslim-majority countries arriving into the US.
In the same year, Mr Khan joined a chorus of British political figures lashing the US president for retweeting a video from a British far right party.
Weighing into this most recent feud on behalf of the UK government, minister Pat McFadden told the BBC London did not have sharia law but rather "British law" and described it as a "great capital city".