The United Kingdom raised its threat level to “critical” late Tuesday, with Prime Minister Theresa May saying another attack could be imminent after 22 people were killed in a bombing Monday night in Manchester.

May said the independent Joint Terrorism Analysis Centre raised the threat level to its highest level as officials continued work to determine whether a “wider group of individuals” are linked to the Manchester attack.

“I do not want the public to feel unduly alarmed,” May said. “We have faced a serious terrorist threat in our country for many years, and the operational response … is a proportionate and sensible response to the threat that our security experts judge we face.”

Key points:

  • U.K. and foreign nationals in the U.K. should exercise caution and expect the possibility of security-related delays when traveling in the U.K.
  • May said that military personnel would be deployed to protect key sites in the U.K. and possibly at concerts, sports matches and other events in the coming days.
  • News reports said that this was only the third time the U.K. has raised its threat level to “critical,” with the first two coming in 2006 and 2007.

Background: Officials raised the threat level after a man set off a bomb at an Ariana Grande concert late Monday in Manchester, leaving 22 dead. The attack drew widespread condemnation, and authorities urged people to exercise caution. The U.S. Embassy in London encouraged “U.S. citizens in the United Kingdom to directly contact family members in the United States.” The embassy further urged people to remain aware of their surroundings “especially in crowds or at large events, and monitor local news sources for updates.” French President Emmanuel Macron and German Chancellor Angela Merkel both released statements expressing shock. “I am following the reports from Manchester with great sadness and shock,” Merkel said. “It is incomprehensible that someone could use a joyful pop concert to kill or seriously injure so many people.”

BAL Analysis: The increased security measures raise the possibility of delays when traveling within the U.K. British and foreign nationals are urged to exercise caution and follow instructions from local authorities, particularly while the threat level remains at its current level. Foreign visitors are advised to register with their home country’s embassy in London, and business travelers may want to make sure their company’s human resources department is aware of their presence in the U.K.

This alert has been provided by the BAL Global Practice group. For additional information, please contact

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