Russia’s intelligence agency has been on a mission to generate “sustained mayhem on British and European streets”, the head of MI5 has said, as he warned the UK faces the most “complex and interconnected” threat it has ever seen.
There have also been 20 Iran-backed plots since 2022, the director general Ken McCallum said.
He said the complex mix of terror-related threats and threats from nation states meant that MI5 had “one hell of a job on its hands”.
A total of 43 late-stage plots to commit “mass murder” in the UK have been foiled since 2017, he said, involving firearms and explosives.
Mr McCallum said the security service’s counter-terrorism work still mostly involved Islamic extremism, followed by “extreme right-wing terrorism”.
But he added there was a “dizzying range of beliefs and ideologies” MI5 had to deal with.
“The first 20 years of my career here were crammed full of terrorist threats. We now face those alongside state-backed assassination and sabotage plots, against the backdrop of a major European land war,” he said.
In a briefing at MI5’s counter-terrorism operations centre in London, Mr McCallum said in the past year, the number of state-threat investigations by MI5 had increased by 48%.
He also expressed concern over the number of young people being drawn into online extremism.
About 13% of those investigated for involvement in terrorism were under 18 – a threefold increase in the last three years, he added.
Separately, Mr McCallum outlined the wide-ranging threats the country faces, which have been exacerbated by the internet.
He said a high proportion of the threat was made up by “lone individuals indoctrinated online”.
“In dark corners of the internet, talk is cheap. Sorting the real plotters from armchair extremists is an exacting task,” he told reporters.
“Anonymous online connections are often inconsequential, but a minority lead to deadly, real work actions.”
He spoke of the difficulty the security service faces while dealing with “volatile, would-be terrorists with only a tenuous grip of ideologies”.
