U.S. Urges Americans in U.K. to Stay Alert After Suspected Terror Plot

The U.S. Embassy in London issued a security alert on 27 September 2026, urging American citizens in the United Kingdom to exercise caution and be mindful of their personal security after a suspected terror plot near a British air base used by U.S. forces. The alert asks U.S. citizens to "notify friends and family of your safety" and to follow instructions from local authorities.

Key facts

• 27 September 2026: U.S. Embassy in London issues a security alert for the U.K.
• Five suspects were arrested near Royal Air Force (RAF) Fairford, Gloucestershire, and later released on conditional bail
• U.K. authorities rate the terrorism threat level as severe
• The U.S. keeps a Level 2 advisory for the U.K.: exercise increased caution
• Americans need an approved Electronic Travel Authorisation (ETA) for stays of six months or less

What happened?

In the early hours of Sunday, 27 September, five suspects were arrested near RAF Fairford in Gloucestershire before an alleged attack could be carried out, according to the alert. RAF Fairford is a British base used by U.S. forces. More than 80 households in the nearby Cotswold village of Whelford were evacuated on Sunday morning; some residents have since returned as advised, while police presence remains in place.

U.K. counter-terror police said they found no explosive devices in the suspicious vans, only "a quantity of petrol". Head of Counter Terrorism Policing Assistant Commissioner Laurence Taylor said on Monday that the investigation is not over and that U.K. and U.S. authorities are working together. U.S. Secretary of State Marco Rubio said the incident "clearly involves the hands of a foreign actor", while President Donald Trump said U.S. and British authorities had been monitoring the suspects.

What is the U.S. advising travellers to do?

The alert tells U.S. citizens to exercise caution, be mindful of personal security and notify friends and family of their safety. It also advises them to review their personal security plans, monitor local media for updates and follow instructions from local authorities.

The State Department notes that U.K. authorities rate the threat of terrorism in the country as severe, meaning an attack is highly likely, and that U.S.-associated facilities, gatherings and organisations may be at heightened risk. Places it lists as possible targets include large gatherings such as sporting events, rallies and holiday events, as well as popular hotels, clubs, restaurants, places of worship, schools, parks, shopping malls, markets and public transport.

What is the current U.S. travel advisory level for the U.K.?

The U.S. maintains a Level 2 travel advisory for the United Kingdom, meaning it considers the country generally safe for tourists who exercise increased caution. The advisory highlights the risk of terrorist violence and attacks, and also warns of isolated violence in Northern Ireland due to political tensions. Petty crime such as pickpocketing and purse or cellphone snatching is described as common in popular tourist areas, with foreigners often targeted.

The State Department advises travellers to stay aware of their surroundings, particularly in crowded tourist locations and transport hubs, and to keep valuables secure. It says medical assistance is usually available locally, though response times may be longer in rural areas, and encourages U.S. citizens to secure medical evacuation insurance. U.K. emergency services can be reached on 999.

Do Americans need a visa for the U.K.?

No visa is required for short stays of six months or less, but U.S. travellers must obtain an approved Electronic Travel Authorisation (ETA) before their trip. Without an approved ETA, an airline or transport provider may deny boarding, or the traveller may be refused entry at the U.K. border.

What this means for travellers

Americans already in the U.K. or planning a trip should review their personal security plans, keep in touch with friends and family, monitor local media and follow instructions from local authorities. Enrolment in the Smart Traveler Enrollment Program (STEP) allows the U.S. embassy or consulate to send updates and alerts and to contact travellers or their emergency contact if needed.

The U.K. remains the most-visited European destination for Americans, with a record 5.6 million U.S. visitors in 2024 contributing £7.3 billion ($9.8 billion). VisitBritain data predicts 5.5 million U.S. visitors in 2026, 4% more than 2025, with an estimated £7.5 billion ($10.2 billion) in spending; London accounts for 48% of visitor nights. The State Department's investigation-related guidance may be updated as U.K. police continue their inquiries.