A Neo-Nazi Helped Incite U.K. Riots. Elon Musk Criticized His Sentencing.

Hours after a deadly knife attack in the northern English town of Southport last July, Andrew McIntyre set up a Telegram channel called “Southport Wake Up.” Amid posts riddled with anti-Islamic, antisemitic and anti-immigrant abuse, he urged people to take to the streets, directing them to a mosque and calling for “war.”

Mr. McIntyre, 39, who took part in two of several riots that rattled Britain last summer, was sentenced to seven years in prison last Monday.

He pleaded guilty to encouraging violent disorder and criminal damage, and to possession of a knife. A day after his conviction, Elon Musk, the billionaire tech mogul, bemoaned Mr. McIntyre’s sentencing in a post on his social media platform X, declaring: “Over 7 years prison for social media posts … Whoever gave that sentence deserves prison themselves.”

“I think it’s really important to note here just how extreme the individuals that Musk has been defending and engaging with in Europe and in the U.K. in recent months are,” said Joe Mulhall, the director of research for Hope Not Hate, a Britain-based advocacy group that researches extremism, particularly on the far right.

While Mr. Musk has used his platform to amplify Tommy Robinson, Britain’s most well-known far-right extremist, the tech billionaire has also spoken out in favor of lesser-known figures like Mr. McIntyre. In doing so, Mr. Mulhall said, Mr. Musk voiced support for a neo-Nazi who has previously been a member of fascist groups.

Mr. Musk did not respond to a request for comment.

The summer riots followed a deadly attack at a dance class in Southport on July 29, in which a knife-wielding assailant killed three young girls and injured several others. Disinformation soon spread on social media, claiming that the suspect, who was later identified as Axel Rudakubana, was a Syrian asylum seeker who had arrived on a small boat, when in fact he was born in Wales.

Research conducted by Hope Not Hate showed that Mr. McIntyre used a Telegram account within hours of the Southport attack to call for violence and then created a TikTok account and Telegram channel to promote it, calling the latter “Southport Wake Up.” He shared a post under a pseudonym in that Telegram channel encouraging a demonstration the next day on St. Luke’s Road in Southport, near the site of the knife attack, and drew a red circle around a mosque on that road. He added the message “time for a 🔥TIME FOR WAR.”

On July 30, a violent mob targeted the mosque that Mr. McIntyre had highlighted, and dozens of police officers were injured. Days of unrest convulsed Britain over the next week, as rioters clashed with the police, lit cars on fire, attacked mosques and ransacked businesses.

Later, in piecing together various accounts run by Mr. McIntyre across social media and messaging platforms, Hope Not Hate found posts from him on Aug. 3, declaring that “The mosques must burn,” and on Aug. 6, calling for the killing of all Jewish, Muslim and Black people, and adding: “White power.”

His extremism extended back years before the riots. Mr. McIntyre posted a selfie in July 2022 in which he gave a Nazi salute, and after his arrest, the police found a copy of “Mein Kampf,” Hitler’s political manifesto, in his home.

The Merseyside Police, which oversee policing in the Liverpool area, said Mr. McIntyre’s messages on Telegram encouraged others to participate in violent disorder and cause criminal damage in Southport. He also made other “failed attempts to instigate disorder at other locations,” the police said in a statement.

Mr. McIntyre took part in riots in Southport on July 30 and in Liverpool on Aug. 3, the police said, and had a knife when he was arrested on Aug. 8.

Paula Jones, a detective inspector with the Merseyside Police, said that Mr. McIntyre had played a key role in coordinating the July 30 riot, using social media to encourage people to travel to Southport and Liverpool to commit criminal damage.

Mr. McIntyre’s social media footprint included graphic threats of rape and violence against other users. “It’s also a useful case study to understand the hypocrisy that sits at the center of Musk when it comes to discussing Britain,” Mr. Mulhall said. “On one hand, Mr. Musk bemoans the abuse of women through grooming gangs, while simultaneously defending the rights of individuals to use social media to send rape threats and death threats to women.”

Mr. Musk’s decision to reinstate the once-banned accounts of other members of Britain’s far right, including Mr. Robinson, has significantly boosted their profile and helped spread extremist ideology, according to groups that monitor the far right. (Mr. Robinson is currently in prison for contempt of court, though his account on X remains active, and supporters are posting in his stead.)

Sophia Gaston, a British policy analyst and a visiting fellow at King’s College London, said that Mr. Musk’s focus on Britain aligned with broader scrutiny of the country by the MAGA movement. Mr. Musk has criticized the British government and authorities for efforts to combat hate speech and violent rhetoric, framing himself as a defender of free speech.

“But there is a difference between that amplification of voices outside of the mainstream of political life and giving a spotlight to those who have been convicted of criminal offenses,” Ms. Gaston said. “In McIntyre’s case, these are not spurious laws around political correctness, which can be open to interpretation. These are laws around public disorder and violence, which are vital to protecting life and property.”