A series of arson and attempted arson attacks on Jewish sites in north-west London has drawn sharp condemnation from Prime Minister Keir Starmer, who vowed to bring perpetrators to justice as community leaders warned of an escalating campaign of antisemitic violence. The latest incident occurred late Saturday night, when officers on patrol noticed a broken window at Kenton United Synagogue in Harrow — a residential borough in north-west London — and found smoke inside a room along with evidence that a bottle containing an accelerant had been thrown through the window. The attack caused minor smoke damage but no injuries or significant structural damage. It followed a similar attempted arson on Friday night targeting a building in nearby Hendon formerly used by the charity Jewish Futures, and an incident on Wednesday near Finchley Reform Synagogue in Barnet, where bottles — one thought to contain petrol — were placed outside the building.

Starmer said he was "appalled" by the attacks and posted on X that they were "abhorrent" and would not be tolerated. "Attacks on our Jewish community are attacks on Britain," he wrote. "We will not rest in the pursuit of perpetrators." Counter Terrorism Policing London is leading investigations into all the incidents, which authorities are treating as linked due to their similar circumstances and online claims of responsibility. The Metropolitan Police has also stepped up deterrence and reassurance patrols across areas with large Jewish populations. Two people were arrested on Wednesday in connection with the Finchley incident.

The attacks form part of a broader pattern that stretches back at least a month. In late March, four Jewish community ambulances were set on fire in Golders Green, also in north London. A little-known group called Harakat Ashab al-Yamin al-Islamiya (HAYI), assessed by the SITE Intelligence Group as having links to Iran, has claimed responsibility for several of the attacks. The group has previously claimed similar attacks in Belgium and the Netherlands.

Chief Rabbi Ephraim Mirvis, the leading religious authority for mainstream British Jewish congregations, described the situation as "a sustained campaign of violence and intimidation against the Jewish community of the UK" that was "gathering momentum." He warned that, while no lives had yet been lost, society must not wait for a fatality before grasping the severity of the moment. The president of the United Synagogue called on Starmer to formally declare "an epidemic of anti-Jewish hate," while the Campaign Against Antisemitism said the attacks reflected a "cataclysmic failure" of politicians, police, and prosecutors to tackle antisemitic extremism over several years.

The incidents have intensified pressure on the government over its approach to foreign-linked extremism. Critics, including the Campaign Against Antisemitism, have renewed calls for the UK to proscribe Iran's Islamic Revolutionary Guard Corps as a terrorist organisation — a step the government has so far declined to take. With counter-terror officers now leading multiple parallel investigations, the coming days will be critical in determining whether authorities can identify those responsible and prevent further attacks on one of Europe's largest Jewish communities.