Elon Musk and His Megaphone, X, Rattle British Politics

When Elon Musk asked his 211 million followers on X to vote on whether “America should liberate the people of Britain from their tyrannical government,” it seemed as if the post could only be tongue-in-cheek.

But coming after a barrage of strident posts about Britain by Mr. Musk — assailing the Labour prime minister, Keir Starmer; demanding the release of a jailed far-right agitator; and breaking with a hard-right leader, Nigel Farage — it came off less as a joke than a flex by a powerful man relishing his ability to roil the politics of another country.

Mr. Musk’s posts, which popped up on X throughout the holiday like unwelcome guests at a Christmas party, have thoroughly hijacked the political debate in Britain at the start of 2025.

On Monday, Mr. Starmer used a news conference about fixing Britain’s National Health Service to deny Mr. Musk’s allegations that he had not acted when he was Britain’s chief prosecutor more than a decade ago against gangs that sexually abused girls.

Mr. Farage, for his part, faced questions about his future as the leader of the right-wing anti-immigration party Reform U.K. after Mr. Musk declared on X on Sunday that “Farage doesn’t have what it takes.” A day later, Mr. Farage posted a call for a national inquiry into the cases of child sexual abuse, picking up on one of Mr. Musk’s favorite causes.

“Musk has a very distorted understanding of British politics, and yet he’s got a megaphone,” said Robert Ford, a professor of politics at the University of Manchester. “When he says this stuff at 3 a.m. on a Sunday night, it disrupts Labour’s whole N.H.S. press conference on Monday.”

The long-term effect of Mr. Musk’s erratic crusade was harder to predict, Professor Ford said, but some of his moves could backfire. His rupture with Mr. Farage, for example, could redound to Mr. Farage’s benefit.

The likely cause of the split was Mr. Farage’s refusal to back Mr. Musk’s demand for the release of the far-right agitator Tommy Robinson. Mr. Robinson, whose real name is Stephen Yaxley-Lennon, is serving a prison sentence for defying a court order by repeating a libel against a young Syrian refugee. He has multiple criminal convictions and a record of racist and Islamophobic statements.

In Britain, Professor Ford said, “Tommy Robinson is political kryptonite. There’s a reason that Farage doesn’t want to have anything to do with him, and never has.”

By rejecting Mr. Robinson in defiance of Mr. Musk, he said, Mr. Farage could make himself more palatable to mainstream voters on the right who are disenchanted by the Conservatives. Mr. Musk, he added, will also find that there aren’t clear alternatives for party leader to Mr. Farage, an architect of Brexit and a fixture in right-wing British politics for decades who galvanized Reform U.K. during last year’s election campaign.

For Mr. Starmer, who returned from a rare vacation that had to be postponed because of the death of his brother, Mr. Musk’s intervention was another setback after a glitch-ridden start to his fledgling government. With his personal ratings plunging in opinion polls, Mr. Starmer was hoping to begin 2025 by rolling out a plan to reduce patient waiting times at the N.H.S.

Instead, reporters asked him about Mr. Musk, who had falsely claimed that Mr. Starmer had covered up the abuse and exploitation of girls in the 2000s and 2010s by gang members, many of whom were of British Pakistani heritage. “Prison for Starmer,” Mr. Musk wrote in one post on Monday morning.

“It probably irritated him beyond description that he has to deal with this kind of thing,” said Steven Fielding, an emeritus professor of political history at the University of Nottingham. The prime minister, he said, was trying to avoid “a street fight” with Mr. Musk and focus on governing.

Mr. Starmer noted that when he was director of the Crown Prosecution Service, between 2008 and 2013, his office brought the first of several cases against a grooming gang and drafted guidelines for the mandatory reporting of child sexual abuse. He had tackled the scandal “head on,” he said.

The prime minister became visibly angry as he defended Jess Phillips, a minister for safeguarding and violence against women and girls, from Mr. Musk’s charge that she was a “rape genocide apologist” because she pushed back on calls for a national inquiry into child sexual exploitation in Oldham, a town near Manchester.

Ms. Phillips had instead called for an investigation to be run by Oldham’s authorities rather than the central government. Mr. Starmer said she had done “a thousand times more than they’ve even dreamed about when it comes to protecting victims of sexual abuse.”

Elizabeth Pearson, the author of a book about Britain’s far-right, “Extreme Britain,” said Mr. Robinson, who had been convicted of assault and fraud, was fortunate to draw “the attention of one of the most powerful people in the West.”

She and other analysts are more puzzled about what Mr. Musk stands to gain from supporting a reviled figure who has occupied the sometimes violent margins of British politics. Daily users of X in Britain have declined since Mr. Musk took over the platform formerly known as Twitter; championing Mr. Robinson’s cause, experts said, is not likely to reverse that trend.

“It is foreign interference in our system,” said Dr. Pearson, a senior lecturer at Royal Holloway, University of London. “I do feel, at the moment, that Musk is becoming a bad actor seeking to destabilize our system.”

Professor Fielding said Mr. Musk was probably catering to his audience in the United States. The risk, he said, was that “anyone who is serious in the U.S. administration will think this man is creating fires that are absolutely unnecessary.”

Mr. Musk’s activism has drawn alarm in other European countries, like Germany, where he endorsed a far-right party with neo-Nazi ties. On Monday, President Emmanuel Macron of France told a diplomatic audience, “Ten years ago, who would have imagined that the owner of one of the world’s largest social networks would be supporting a new international reactionary movement.” He did not mention Mr. Musk by name.

Likewise, Mr. Starmer showed no appetite to single out Mr. Musk, a close ally of President-elect Donald J. Trump, with whom Mr. Starmer and his aides have tried to cultivate relations. “This isn’t about America or Musk,” he said to a reporter on Monday. “I’m talking about our politics.”