London's Mayor, Sadiq Khan, has issued a stark warning about the rise of far-right movements in the West, including the United States, France, and Germany.

Speaking ahead of Donald Trump's upcoming second inauguration as President of the United States, Khan emphasized the urgency of addressing resurgent far-right ideologies, particularly online, and called for the implementation of stricter regulations against harmful content.

Khan's remarks coincide with a gathering of far-right figures in the US for Trump's inauguration, including Italy's Prime Minister Giorgia Meloni and Éric Zemmour, a former French presidential contender known for xenophobic rhetoric.

In an article for the _Observer_, Khan also criticized major social media platforms and their financial supporters for enabling the spread of far-right materials by prioritizing profits over democratic values.

Highlighting the importance of defending liberal democracy, Khan described the current climate as a 'century-defining challenge,' citing historical parallels with the 1920s and 1930s.

He urged world leaders, including those in the UK, to speak out against extremist actions and rhetoric from influential political figures, including incoming President Trump.

The remarks follow UK Foreign Secretary David Lammy's recent comments, where he emphasized the importance of maintaining strong alliances, despite past criticisms of Trump.

Khan, a frequent target of Trump's online insults during his previous presidency, called for increased pressure on social media companies to address issues of hate speech and misinformation, particularly accusing Elon Musk of enabling the return of far-right figures on platform X, formerly known as Twitter.

The UK government is closely examining recent changes in social media policies, including Meta's decision to reduce restrictions on certain topics.

This scrutiny comes ahead of the implementation of the Online Safety Act in March, which will require platforms to remove illegal disinformation and content harmful to children.

While the government seeks investment from tech firms, Science and Technology Secretary Peter Kyle has affirmed that online safety will not be compromised.

A government spokesperson reiterated the commitment to combat extremist content, emphasizing ongoing cooperation with law enforcement, local communities, and international partners, and urging social media companies to proactively tackle misinformation and disinformation on their platforms.