MI5 Director General Ken McCallum issued a warning about the growing complexity of security threats facing the UK, British media said Tuesday.
McCallum spoke from MI5's counter-terrorism operations center in London where he revealed that the agency is contending with an unprecedented combination of challenges that is "the most complex and interconnected" threat landscape in MI5's history.
He specifically pointed to Russia's intelligence agency, accusing it of orchestrating efforts to create "sustained mayhem on British and European streets."
McCallum outlined a sharp rise in Russian-backed "arson, sabotage, and more dangerous actions" as part of the country's Moscow's covert operations.
More than 750 Russian diplomats, many of whom were suspected spies, have been expelled from Europe since Russia invaded Ukraine in 2022, he said.
Russian state actors, however, have increasingly turned to private intelligence operatives to carry out their operations, said McCallum, who noted that the proxies were less professional and easier to disrupt.
- MI5 responded to 20 Iran-backed plots since 2022
The MI5 chief also highlighted the alarming rise of threats from Iran, indicating that 20 Iran-backed plots targeting UK citizens and residents have been foiled since 2022.
The plots, he said, posed "potentially lethal" risks and represented a growing concern for the intelligence services.
In addition to state-sponsored threats, the UK continues to face the enduring menace of terrorism.
McCallum reported that since 2017, his agency has successfully thwarted 43 late-stage terror plots involving firearms, explosives and plans to commit mass murder.
The majority of MI5 counter-terrorism work remains focused on Islamic extremism, accounting for 75% of cases, with right-wing terrorism making up the rest.
McCallum noted that a growing number of young people are being drawn into extremism, especially through the internet.
Thirteen percent of those investigated for terrorism offenses are now under 18 -- a troubling threefold increase in the past three years, according to MI5.
The rise of "lone individuals indoctrinated online" poses a particular challenge for the agency, said McCallum, adding that while most online extremists are "armchair plotters," some turn their rhetoric into deadly, real-world actions.
"In dark corners of the internet, talk is cheap. Sorting the real plotters from armchair extremists is an exacting task," he said, highlighting the difficulties in identifying those who might act on their radical beliefs.
He also expressed concern for "volatile, would-be terrorists with only a tenuous grip of ideologies," complicating MI5's efforts to predict and prevent attacks.
Looking ahead, McCallum underscored the sheer scale of the threat facing the UK.
In the last year alone, MI5 has seen a 48% increase in investigations into state-sponsored threats.
As the agency grapples with this surge in threats from hostile nations and domestic terrorism, McCallum acknowledged the weight of the task: "MI5 has one hell of a job on its hands."
