Five men detained near an RAF base used by the US have been arrested on suspicion of preparing a terrorist act.
A major incident was declared and 85 homes evacuated near RAF Fairford in Gloucestershire after several men were arrested by armed police on suspicion of explosives offences on Sunday morning.
Counterterrorism police and detectives leading the response are said to be investigating whether the alleged plot is linked to Iran, according to The Times.
Detectives are reported to be keeping an open mind, but one line of inquiry is likely to be whether the incident is connected to Tehran because the base hosts the United States Air Force (USAF) and has been used to launch operations against the Islamic republic.
US president Donald Trump claimed the alleged plot was “looking to do big damage” as he praised the joint operation with UK law enforcement.
“We had them under investigation,” he told reporters in the US. “They were looking to do big damage to our fort, and working with the British worked out great.”
No declaration of a terrorist incident has been made as of Sunday night.
Four USAF bombers landed at RAF Fairford this spring after then-prime minister Sir Keir Starmer granted permission for “defensive” US action against Iranian missile sites from UK bases.
In July, the British government insisted it “stands ready 24/7 to defend itself” after Iran said UK airbases used by the US were considered “legitimate targets”.
Following the arrests on Sunday, aerial footage from the village of Welford, near the base, showed a British army bomb disposal squad using specialist robotic equipment to examine three white vans stopped by armed police during the incident.
A force spokesperson said: “At around 12.45am, police received a call relating to three suspicious vehicles, which appeared to be travelling towards the air base.
“Armed officers responded and five men were arrested in the Whelford area on suspicion of committing offences under the Explosives Act. They were further arrested on suspicion of preparation of a terrorist act, contrary to section 5 of the Terrorism Act.”
Investigators were working to analyse any devices seized from those arrested to establish details of any plot and any potential motivation. On Sunday night a 400m cordon remained in place around the vehicles.
Maggie Blyth, the temporary chief constable of Gloucestershire Police, told reporters she believed the incident was contained following the “swift” arrests.
She said: “This is a fast-moving situation and all agencies across Gloucestershire are actively working to respond to our communities’ needs and continue to provide information to our communities on a regular basis, we will also continue to assist counter-terrorism policing with their investigation and liaise with other national partners.”
RAF Fairford had been raised to the highest threat level, Delta, while US airbase Lakenheath in Suffolk is on Charlie alert, the second-highest threat level that can be issued by the US Department of Defense.
The police operation near the village of Whelford in Gloucestershire was not intelligence-led, meaning investigators had not known about any potential plot in advance.
A resident of Whelford said she called police after she seeing three vans “blocking the road”, before spotting a “large group of hooded and ‘balaclava’d’ men”. The resident, who asked not to be identified, said she was driving home in the early hours of Sunday morning.
After making the 999 call, she said police arrived 15 minutes later.
She said: “A plucky amateur shouldn’t be spotting an unusual bit of activity at 1am when the air base is on high alert. I think it’s absolutely astonishing.”
Julian Tudsbery, who has lived in Whelford for 30 years, said: “(The police) were then banging on the door, so I went downstairs in my dressing gown. There were several police, three police cars in the drive, and they said you need to evacuate, there’s been a major incident, said he couldn’t elaborate.”
A spokesperson for the US Air Force said its personnel based at RAF Fairford “remain vigilant”.
“For operational security reasons we will not discuss specific force protection measures,” the spokesperson added.
“The 501st Combat Support Wing and our fellow UK-based wings remain vigilant and will take appropriate actions to ensure the safety and security of our US service members, civilians, contractors, and their families.
“We constantly assess a variety of factors that determine what measures we institute or modify to protect our installations, our people and their families.”
Security measures at the site in southwest England have significantly increased, with roadblocks and armed police preventing access and emergency vehicles parked nearby, Reuters reported on Sunday.
The airbase also hosts the annual Royal International Air Tattoo (RIAT), though this year’s event in May was cancelled because of the military operations.
A government spokesperson added: “We are grateful to the emergency services, who have acted quickly to detain several suspects and put measures in place to keep the community safe.
“It would be inappropriate to comment further whilst investigations are ongoing.”
Defence secretary Wes Streeting confirmed the incident is “being dealt with” and thanked the emergency teams who acted “so swiftly”. “It is exactly why our emergency response teams and armed forces are on standby 24/7,” he added.
