Iran is trying to hit military sites in the U.K. and the suspected plot to attack a U.S.-run military air base in September is “not unique,” the head of Britain’s MI5 spy agency said on Tuesday (October 13, 2026).

Ken McCallum, who leads the UK’s domestic security service, said Tehran is seeking to intensify its attacks in Britain beyond the traditional targets of Iranians opposed to the country’s Islamic authorities.

That has included arson and sabotage attacks on Jewish sites that Britain says were carried out by Iranian proxies.

Mr. McCallum said another “major shift this year has been Iranian ambitions to come at harder targets, like military sites.”

The incident at RAF Fairford “is not unique. There have been other examples, not just in the UK but around the world,” Mr. McCallum said.

Mr. McCallum delivered a speech outlining major threats to the U. K.as detectives investigate a suspected terror plot against the U.S.-run base in western England, which has been used to bomb Iran during this year’s war.

Scores of residents were evacuated from their homes near the base on September 27 as armed police officers and army bomb-disposal experts swarmed the rural area. Police later said they had found a quantity of an accelerant — gasoline — in three vans at the site, but no explosives.

British authorities have linked Tehran to the incident, which led the U.S. to pull its bombers from RAF Fairford. Prime Minister Andy Burnham said on Monday (October 12) that the apparent plot was “almost certainly” directed by Iran’s Revolutionary Guard.

Seven men in their 20s have been arrested and released on bail under investigation.

Iran has denied involvement, although it has previously said that it considers any base used to attack its territory a legitimate target.

MI5 says AI could bring bioweapon risk

In a stark speech, Mr. McCallum argued that the U.K. faces a “new era of national security” and is at a turning point equivalent to the 9/11 attacks a quarter century ago.

He said his agency’s work countering state threats – chiefly from Russia, Iran and China – has quadrupled in the past decade, and claimed that both Russia and Iran are expanding their hybrid warfare campaigns against the U.K.

“Meanwhile, technology is racing ahead, with artificial intelligence “supercharging” the cybersecurity battle between attackers and defenders,” he said.

Mr. McCallum said terror plotters have used artificial intelligence for reconnaissance and attacks, including AI-enabled drones. Even more concerning, he said, is “AI’s potential to change the stakes on existing or even new bioweapons.”

He said terror groups “would dearly love” to have chemical, biological or radiological weapons, but these are hard to obtain.

“One risk is that AI could enable dangerous knowledge to get into the hands of people we would all rather didn’t have that knowledge,” he said. “A second and different risk … is the possibility that AI could generate novel pathogens not previously seen.”

Mr. McCallum said MI5 has set up a new AI Threat Assessment Centre to try to keep ahead of the risks.

“Human history has given us no experience of facing an actor which is smarter than we are. It is capable of outthinking us. This is genuinely novel, and deserves the serious attention it is getting, including in MI5,” he said.

British Prime Minister Andy Burnham said on Monday (October 12, 2026) that a suspected plot ​targeting the RAF Fairford air base in Britain was “highly likely” ‌to have been coordinated in Iran, and almost certainly ​directed by the Islamic Revolutionary Guard Corps.

The RAF ⁠Fairfordbase had been used by U.S. bombers to carry out strikes on Iran but last week, U.S. President Donald Trump said a ‌threat linked to Iran had prompted the removal of the planes.

U.S. officials have told Reuters that ‌there had been a suspected plot involving Iran ‌to ⁠launch a drone attack.

“I can confirm our assessment ⁠that it is highly likely to have been coordinated in Iran, almost certainly directed by Iran’s Islamic Revolutionary Guard (IRGC),” Mr. Burnham told Parliament.

The alleged plot ​came to light when ‌five British men were arrested in the early hours of September 27 by three vans near the base on suspected terrorism and explosive offences.

They were later released ‌without charge on police bail “under stringent conditions”. Police ​said petrol but no viable explosive had been found in the vans, and detectives said they were ⁠considering whether a foreign state had been involved.

Two other men, including a British-Iranian national, have also been arrested and ‌released.

“We will not tolerate these threats on our soil,” Mr. Burnham said. “We will crack down on Iran’s use of criminal networks, using our full range of powers to target them and their funding streams, and we will bring further sanctions to restrict the capacity of Iran and the ‌IRGC to do us harm.”

Iran has rejected any suggestion it ​was involved in the incident at Fairford, saying it amounted to “unfounded and malicious speculations”.

The British authorities have ⁠accused Iran of being involved in numerous plots in Britain.

In July, ⁠Britain used new powers designed to stop the use of state-sponsored proxies to ban support for ‌the IRGC and a linked group accused of being behind attacks at locations linked to Jewish and Israeli ​communities, and Persian-language media.

The British police questioned five men on Monday (September 28, 2026) on suspicion of explosives-related and terrorism offences after they were detained near an air base that has been used by the U.S. to strike Iran.

Officers detained the men in the early hours of Sunday (September 27, 2026) after they received a tip-off that three large white vans had been seen heading to the military airfield of Royal Air Force (RAF) Fairford in western England.

U.S. President Donald Trump said the suspects had been looking to do “big damage” and had been under investigation by British and U.S. authorities. However, a local farmer said she had tipped off the police after seeing a group of “hooded and masked men” running into the fields.

British counterterrorism detectives have not yet publicly said who they believed was involved, but a source familiar with the investigation said an Iranian-linked motive was considered most likely, while a Russian sabotage operation or an Islamist plot was also being examined.

Defence Minister Wes Streeting told BBC News on Monday that he would not speculate about the motives of a live investigation. On the general Iranian threat to the country, he said, “We know that Iran and their proxies wish to do us harm. We know that they hate our democracy, and we know that we regularly have to thwart Iranian attempts to threaten either our interests or indeed our allies.”

In May, Britain sanctioned 12 individuals and entities linked to Iran, accusing them of involvement in hostile activity including plotting attacks and providing financial services to groups seeking to destabilise the U.K. and other countries.

Iran has repeatedly denied involvement in attacks or plots in the U.K. and elsewhere.

Base cordoned off

The British government had authorised the U.S. to use bombers based at Fairford to strike Iranian missile sites that were attacking ships in the Strait of Hormuz.

The government has said Prime Minister Andy Burnham is being regularly updated on the incident, and he cancelled at least two of his engagements at the Labour Party’s annual conference on Sunday.

Iran’s Revolutionary Guards had warned Britain in July not to allow U.S. bombers to fly from Fairford, saying any base used to launch attacks would be a legitimate target.

In Fairford, the police have imposed a 400-metre cordon around the base and evacuated residents from 85 homes.

A bomb disposal robot could be seen on Sunday operating around the three white vans, while security was stepped up around the base. Armed police stood guard at the main entrance while large machinery was used to block other access points. Security was also stepped up at other U.S. bases in Britain.