A suspected plot to attack a U.S.-operated military air base in England was “almost certainly” orchestrated by Iran’s Revolutionary Guard, British Prime Minister Andy Burnham said Monday.

Burnham had previously said there were strong indications that Iran was linked to the apparent plan last month to attack the RAF Fairford air base, which American bombers have used to strike Iran in the ongoing war.

In the course of the investigation into the alleged plot, police have arrested seven men; however, all of the suspects have since been released on bail, and no charges have been brought against anyone thus far.

Iran has denied any involvement, though it has previously stated that it regards any base employed to launch attacks against its territory as a legitimate target.

"I can confirm our assessment that this was highly likely coordinated in Iran, almost certainly directed by Iran's Islamic Revolutionary Guard," Burnham told lawmakers.

"We will not tolerate these threats on our soil."

On Sept. 27, many residents living near the air base were evacuated from their homes as armed police officers and army bomb-disposal experts flooded into the rural area.

Police later said they had found a quantity of an accelerant — gasoline — in three vans linked to the initial five suspects arrested on the scene, but no explosives.

All the suspects apprehended are in their twenties.

None has been identified, though police stated that six are British nationals, while one holds dual U.K.-Iranian citizenship.

On Monday, the British government summoned the Iranian ambassador, who reiterated that Tehran was not involved in the suspected plot and urged the U.K. to provide evidence supporting its claims.

The U.K. also said it added two Iranians to its sanctions list, including the head of counterespionage operations in the Revolutionary Guard.

Authorities said the two were involved in carrying out espionage and attacks on behalf of Iran's government in Europe and the U.S.

The Pentagon announced that the U.S. had withdrawn its bombers last week from RAF Fairford, situated roughly 100 miles (160 kilometers) to the west of London, and that the aircraft have since been redeployed to their home bases.

The Trump administration has stated that it believed the base was confronted with Iranian threats aimed at killing as many American troops and destroying as many U.S. aircraft as possible.

The British government permitted the U.S. military to use RAF Fairford for what it described as defensive strikes on Iranian missiles and their launch sites, after Iranian attacks on U.K. interests and Britain's allies in the Gulf.

Officials have said that local proxies linked to Iran were behind a string of arson and other attacks on the U.S., Britain and other countries, many of them targeting Jewish communities and intended to sow fear.

British officials have said that the number of national security cases involving activity by hostile states, including Iran, rose by 50% in the six months to December 2025.

Home Secretary Shabana Mahmood said Monday that the Fairford air base incident “speaks to a wider trend.”

“States like Iran are using proxies to conduct hostile activity here in Britain.

They pay criminals or exploit naive volunteers, attacking our country and its citizens while maintaining an air of plausible deniability,” she said.

In a joint statement released Monday, the foreign ministers of the U.K., U.S. and about two dozen Western countries condemned Iranian attacks on their territory.

They said the Fairford incident demonstrated Iran's "continued willingness to project hostile activity beyond its borders through covert networks and proxy actors."

“Anyone who carries out hostile activities on behalf of Iran, or any other state, should know that we will take action to identify, investigate, disrupt, and prosecute these acts,” the statement said.