Britain publicly blamed Iran’s Islamic Revolutionary Guard Corps (IRGC) on Monday for a suspected terrorist operation targeting RAF Fairford, a key British airbase used by American forces during strikes against Iran. The announcement followed an unusual U.S. military withdrawal from the installation after intelligence warnings raised concerns about the safety of American aircraft and personnel.

Prime Minister Andy Burnham told Parliament that British intelligence assessed the September 27 incident was “highly likely to have been coordinated in Iran, almost certainly directed by Iran’s Islamic Revolutionary Guard [Corps].” The accusation marked Britain’s strongest public attribution yet regarding the suspected plot.

The threat prompted the Pentagon to withdraw all 12 B-1 bombers stationed at Fairford earlier this month. The aircraft had been operating from the base, located roughly 100 miles west of London, as part of the American military campaign against Iran known as Operation Epic Fury.

The evacuation reportedly followed warnings received by American commanders as early as mid-September that the base could face an Iran-backed attack. Additional intelligence in early October heightened concerns, leading to the sudden departure of the bombers. Some aircraft reportedly left while aerial refueling planes were still being deployed to support their flights back to the United States.

President Donald Trump confirmed last week that security concerns, rather than a routine rotation, prompted the withdrawal.

“There were some threats,” Trump said. “Why should we leave them there?”

The president declined to confirm whether Iran had brought combat drones into Britain but warned Tehran would “suffer greatly” if it was responsible. Vice President JD Vance separately said Secretary of War Pete Hegseth ordered the withdrawal “out of an abundance of caution” to protect American personnel, adding that the administration believed “with some confidence” Iran was pursuing attacks against U.S. interests.

The security investigation intensified on September 27, when British police arrested five men traveling in vans near RAF Fairford. Authorities evacuated 85 nearby homes and deployed a bomb-disposal robot to examine the vehicles, but no explosives were found. Two more suspects were subsequently arrested, bringing the total to seven. All have been released on bail, and none has been charged.

Officials have not established publicly whether those arrests were connected to the suspected operation against American aircraft or involved a separate potential threat. U.S. and British officials have described the suspected plot as a complex effort to destroy military aircraft and kill American personnel. Some reportedly believed the plan may have drawn inspiration from a Ukrainian operation that used drones concealed in trucks to strike Russian airbases in 2025.

Concerns have also extended to American military installations in Germany. Israel reportedly warned German officials about heightened risks to U.S. facilities, specifically identifying Ramstein and Spangdahlem airbases.

The IRGC had warned in July that British bases used by American forces to launch strikes against Iran would be considered legitimate targets. Following Monday’s assessment, Burnham vowed to intensify Britain’s response.

“We will not tolerate these threats on our soil,” the prime minister said, pledging to target Iranian-linked criminal networks and their funding streams while imposing additional sanctions against Tehran and the IRGC.

Home Secretary Shabana Mahmood said British authorities believed the suspected operation was likely coordinated by a known individual based in Iran, although officials have not publicly identified that person.

Britain also announced sanctions against two Iranian nationals accused of involvement in separate hostile operations: Ruhollah Bazghandi, identified as an IRGC counterespionage official, and Shahram Ali Reza Tamarzadeh Jakki, who has been linked to the Zindashti Network. The sanctions include asset freezes, travel bans and restrictions on serving as company directors. British officials did not present the measures as evidence that either individual directed the Fairford incident.

Foreign Secretary Ed Miliband summoned Iranian Ambassador Seyed Ali Mousavi over the allegations. The United States and 27 other countries joined Britain in condemning Iranian hostile operations, including suspected plots involving violence, sabotage and covert networks.

A joint statement said the Fairford incident demonstrated the IRGC’s willingness to project hostile activity beyond Iran’s borders through covert networks and proxy actors. The participating governments pledged to investigate and prosecute those responsible for hostile operations conducted on Tehran’s behalf. Secretary of State Marco Rubio also spoke with Miliband on Monday about holding Iran accountable and protecting American assets in Britain.

Trump offered no specific announcement of additional military action when asked outside the White House whether Washington would respond to Britain’s findings.

“We’re going to see,” the president said, pointing to Iran’s losses in the ongoing war and adding that the country had “no Navy” and “no air force.”

Iran rejected Britain’s accusations as baseless, arguing that London had failed to present evidence and was attempting to deflect attention from its support for the U.S.-Israeli military campaign. Tehran specifically challenged Britain’s use of the phrases “highly likely” and “almost certainly,” insisting those assessments did not substantiate the allegations.

Although no charges have been filed against the seven men arrested near Fairford, Britain’s public attribution to the IRGC has escalated the diplomatic confrontation. The suspected plot has already prompted an extraordinary withdrawal of American strategic bombers from an allied base, while London and Washington weigh further steps to protect their military personnel and installations.