LONDON — Tommy Robinson, the controversial British activist born Stephen Yaxley-Lennon, went live on social media early Wednesday morning claiming he had received a veiled threat intended to silence his commentary on sensitive political and cultural issues.

The unscheduled broadcast, which began around 3 a.m. local time, showed Mr. Robinson seated at a simple desk in dim lighting. Speaking directly into his phone camera without notes or production assistance, he described receiving a message from what he called a “verified account connected to a very powerful figure.”

According to Mr. Robinson, the message read: “Keep speaking about matters that do not concern you — and don’t assume the power structures of this world will protect you.” He characterized the communication as a direct warning rather than routine criticism.

Mr. Robinson, known for his outspoken criticism of Islam, immigration and what he describes as failures of multiculturalism in Britain, has long positioned himself as a target of establishment pressure. He has faced multiple legal convictions, including for contempt of court and defamation, and maintains that authorities and powerful interests seek to marginalize him.

In the livestream, which lasted roughly 15 minutes, he spoke calmly but gravely about “invisible pressures” on public figures who challenge prevailing narratives. He said this was not the first such warning he had received.

“I’ve been told honesty can come at a cost,” he stated. “That speaking plainly is welcomed — until it becomes inconvenient.”

He emphasized that the latest message felt different, suggesting a clearer line had been drawn. Mr. Robinson told viewers he chose to broadcast live immediately, without intermediaries or editing, to document the alleged intimidation in real time.

The video showed his phone vibrating during the stream. He placed it face down on the desk and continued speaking about personal responsibility and the dangers of silence under pressure.

“If from this point forward my voice, my work, or my ability to speak freely faces obstacles,” he said, “people will know where that pressure came from.”

Mr. Robinson concluded by stating he would not step back from his positions. “I’m not provoking anyone,” he added. “I’m simply standing where conscience tells me to stand — in truth and in the open.”

The livestream ended with an empty chair visible as the broadcast continued for some time. Clips and full recordings spread rapidly across social media platforms, drawing polarized reactions.

Supporters praised Mr. Robinson for what they viewed as courage in the face of intimidation. Critics dismissed the event as another instance of self-dramatization designed to boost his profile and fundraising.

Mr. Robinson has built a significant following through his activism, books and online presence, particularly among those concerned about rapid demographic change and grooming gang scandals in parts of Britain. His detractors, including anti-extremism groups and mainstream politicians, accuse him of stoking division and promoting conspiracy theories.

No independent verification of the alleged threatening message has emerged. British police have not publicly commented on any specific threat reported by Mr. Robinson related to this incident.

The episode arrives amid heightened tensions in Britain over issues of free speech, integration and political polarization. Recent years have seen intense debates about online safety laws, protest rights and the boundaries of acceptable discourse.

Legal experts note that while genuine threats are taken seriously by authorities, public figures frequently report vague warnings or harassment that prove difficult to substantiate. Mr. Robinson himself has a long history of legal troubles, including bankruptcy and prison time for various offenses.

Social media’s role in amplifying such moments has grown. Livestreams like this allow activists to bypass traditional media gatekeepers, reaching audiences directly but often without rigorous fact-checking.

Mainstream outlets have historically approached Mr. Robinson’s claims with caution, citing his pattern of inflammatory rhetoric and past inaccuracies. Supporters counter that legacy media ignores or suppresses legitimate concerns he raises.

The 3 a.m. broadcast fits Mr. Robinson’s style: unpolished, urgent and confrontational. It has already generated significant engagement online, with thousands sharing the video and speculating about the identity of the “powerful figure” behind the message.

Broader questions of safety for activists on all sides persist. Britain has seen rising concerns about threats to journalists, politicians and public commentators amid polarized debates on immigration and identity.

Whether this particular claim leads to any formal investigation or simply adds to the cycle of online contention remains to be seen. For now, it underscores the deep fractures in British society over who gets to speak, on what topics, and at what personal risk.

Mr. Robinson has announced plans to continue his activities, telling viewers in the stream, “See you tomorrow. Or not. That part isn’t up to me.”