The United States Embassy in London issued a formal security alert on Friday, May 1, 2026, urging American citizens in the United Kingdom to exercise heightened caution after British authorities raised the national terrorism threat level to severe, the second-highest designation on the country’s five-tier scale.
The upgrade, announced on Thursday, April 30, came one day after a knife attack in Golders Green, north London, in which two Jewish men aged 34 and 76 were stabbed in separate incidents within minutes of each other. The Metropolitan Police declared the attack a terrorist incident. Essa Suleiman, 45, a British national born in Somalia who came to the United Kingdom as a child, was subsequently arrested and charged with two counts of attempted murder in connection with the stabbings, and a third count relating to a separate incident elsewhere in London the same morning.
The threat assessment was carried out by the Joint Terrorism Analysis Centre (JTAC), an independent body based within the United Kingdom’s domestic intelligence service, MI5. JTAC said the upgrade from substantial to severe was not solely driven by the Golders Green attack, but reflected a broader and sustained rise in both Islamist and extreme right-wing terrorist threats from individuals and small groups operating within the country. MI5 noted that the threats were particularly directed at Jewish and Israeli individuals and institutions against the backdrop of the ongoing conflict in the Middle East.
Home Secretary Shabana Mahmood described the Golders Green attack as “abhorrent” and a vile act of terrorism, acknowledging the anxiety the incident had caused within the Jewish community.
Metropolitan Police Commissioner Sir Mark Rowley said the suspect had a history of serious violence and mental health issues, and had previously been referred to the government’s Prevent counter-terrorism programme in 2020, though that referral was closed the same year. An Iran-linked group, Harakat Ashab al-Yamin al-Islamia, claimed responsibility for the attack.
In response, the United States Embassy advised American nationals to remain alert in crowded public spaces including schools, hospitals, places of worship, tourist sites, and transport hubs. It also urged citizens to vary their travel routes and times to reduce predictability, keep a low profile, review personal security plans, and report suspicious activity or social media threats to local authorities.
The alert represents the second security notice from the United States Embassy in London in recent weeks. An earlier notice had cautioned American citizens about attacks and threats targeting Jewish and American institutions in the United Kingdom and across Europe.
The upgrade to severe means British security services now consider a terrorist attack highly likely within the country.
