Sir Keir Starmer has opened the door to banning some pro-Palestinian demonstrations, declaring that chants of “globalise the Intifada” cross a line that Britain can no longer tolerate. Speaking after the stabbing of two Jewish men in the north London suburb of Golders Green—an attack the Metropolitan Police has classified as terrorism—the Prime Minister told the BBC that the country had entered “a completely new phase”. The remarks mark a significant shift in tone from a government that has long defended the right to protest, even as weekly marches against the Gaza war have drawn hundreds of thousands.

Viewed from Westminster, Starmer’s intervention is a direct response to a palpable sense of siege inside the Jewish community, a sentiment that boiled over when he was booed during a visit to a volunteer ambulance service in Golders Green on Thursday. The assailant, Essa Suleiman, a 45-year-old British citizen of Somali origin, has been charged with three counts of attempted murder—two for the Golders Green attack and one for an unrelated stabbing near Tower Bridge earlier that same day. He made his first appearance at Westminster Magistrates’ Court on Friday and was remanded in custody.

The attack prompted the Home Office to raise the national terrorism threat level from “substantial” to “severe”, the second-highest rung, meaning an assault is now judged highly likely. Mark Rowley, the Metropolitan Police Commissioner, described the country as facing “something of an epidemic of antisemitism” and warned that the police would review all future events in light of the changed threat environment. That review already has concrete implications.

On 16 May, a pro-Palestine march planned to coincide with Nakba Day—the annual commemoration of the 1948 displacement of Palestinians—will overlap with a rally promoted by the far-right activist Tommy Robinson and the FA Cup final at Wembley. Police have announced strict conditions on routes and gathering points to prevent serious disorder. Across the Atlantic, commentators in Canada’s National Post urged politicians to watch Starmer’s response closely, arguing that flat platitudes about antisemitism are no longer sufficient.

But the political fallout has been messy. Zack Polanski, the leader of the Green Party, was forced to apologise after sharing a social media post that accused police of using excessive force when they Tasered and kicked Suleiman during his arrest. Starmer called Polanski’s actions “disgraceful” and said he was unfit to lead any party.

Analysts in London note that the stabbing—and the subsequent row over policing—has sharpened a wider debate about the cumulative effect of repeated protests on community cohesion. Starmer himself has pointed to France, where authorities have banned certain demonstrations, as a model Britain might follow. Yet any ban would face legal and political headwinds.

The coalition behind the marches, Stop the War, denies any link between the Golders Green attacker and their planned event, and insists that the vast majority of participants are peaceful. The challenge for the government now is to calibrate a response that protects public safety without inflaming the very tensions it seeks to calm. With two high-risk demonstrations on the horizon and a terror threat that shows no sign of receding, the coming weeks will test whether Starmer’s “whole of society” rhetoric can be translated into durable policy.