From Hearst to Murdoch, the power of “media moguls” has posed a challenge for governments since the birth of mass media. They have never confronted anyone quite like Elon Musk. The world’s richest man is both the owner of X and, with 194mn followers, the most-followed figure on the social media platform previously called Twitter, giving him a bully pulpit of extraordinary reach. Business interests spanning technology, manufacturing, space and defence make him a figure many politicians are reluctant to tangle with. Yet recent weeks have highlighted the pitfalls of such a concentration of influence in this “free speech absolutist”.

In the UK, Musk’s X has been a conduit for content that helped to foment anti-immigration riots across English cities. His own posts fanned the flames. He declared that “civil war is inevitable” in Britain, shared a fake story posted by a far-right group, and launched jibes about prime minister Sir Keir Starmer. X was resistant to calls to take down posts that the UK government’s disinformation unit deemed a threat to national security.

In the US, where Musk has previously spread his political bets but is now backing Donald Trump to return to the White House, monitors have found at least 50 of his posts on the 2024 election — together amassing 1.2bn views — have been refuted by independent fact-checkers. This week, X livestreamed his distinctly softball, if rambling, two-hour interview with Trump.