Britain is facing a "staggering rise" in attempts at assassination, sabotage and other crimes on U.K. soil by Russia and Iran, as the two states recruit criminals to "do their dirty work," the head of Britain's domestic intelligence agency said Tuesday.
MI5 Director General Ken McCallum said his agents and police have tackled 20 "potentially lethal" plots backed by Iran since 2022 and warned that it could expand its targets in the United Kingdom if conflicts in the Middle East deepen.
So far, the threats have been aimed at Iranians abroad who oppose the country's authorities. But McCallum said there is the risk "of an increase in — or broadening of — Iranian state aggression in the U.K." if the Middle East crisis escalates with Israel launching a major attack in response to Iran's recent missile barrage.
In a rare public speech setting out the major threats to the U.K. from both states and militant groups, McCallum argued that hostile states, radicalized individuals and a revived Islamic State group have combined to create "the most complex and interconnected threat environment we've ever seen."
McCallum said there also is a risk that Israel's conflicts with Iran-backed groups — the militant Hamas in Gaza, Hezbollah in Lebanon as well as the Houthi rebels in Yemen — could trigger attacks in the U.K., though so far the crisis has not translated "at scale into terrorist violence" in Britain.
The number of state-threat investigations undertaken by MI5 has risen by 48% in the past year, with Iran, Russia and China the main perpetrators, McCallum told journalists at the U.K.'s counterterrorism command center in London.
McCallum said that since the death of Mahsa Amini, who died in Iranian police custody in September 2022 after being detained for allegedly violating the Islamic republic's mandatory headscarf law, "we've seen plot after plot here in the U.K., at an unprecedented pace and scale."
He said MI5 and the police have responded to 20 potentially lethal Iran-backed plots since January 2022, up by a third from the figure of 15 the government gave at the end of January.
McCallum said Russia's military intelligence agency was trying to use "arson, sabotage and more" to create "mayhem" on the streets of Britain and other European countries.
Both Russia and Iran often turn to criminals, "from international drug traffickers to low-level crooks," to carry out their illegal deeds, he said.
Several alleged state-backed plots have led to criminal charges. In December, a Chechen man was jailed for allegedly carrying out reconnaissance on the offices of a dissident Iranian broadcaster in London. Separately, several suspects are awaiting trial in London over an alleged Russia-linked plan to attack Ukrainian-owned businesses.
Britain is not alone in pointing a finger at Moscow and Tehran. Germany has arrested several people for allegedly spying or planning attacks on behalf of Russia. In May, Sweden's domestic security agency accused Iran of using criminal networks to target Israeli or Jewish interests in the Scandinavian country.
Past speeches by McCallum and other U.K. intelligence chiefs have emphasized China's increasingly assertive behavior, which in 2022 McCallum called Britain's greatest "strategic challenge." On Tuesday, McCallum stressed the importance of the U.K.-China economic relationship but said there were "risks to be managed."
The U.K.'s official terror threat level stands at "substantial," the middle of a five-point scale, meaning an attack is likely, and McCallum said that since 2017, MI5 and the police have disrupted 43 late-stage plots, saving "numerous lives."
While about three-quarters of the plots stem from Islamic extremist ideology and a quarter from the extreme right, he said those labels "don't fully reflect the dizzying range of beliefs and ideologies we see," drawn from a soup of "online hatred, conspiracy theories and disinformation." Young people are increasingly involved, he said, with 13% of the subjects of MI5 terror investigations under the age of 18.
He also said there were worrying signs that the Islamic State group is attempting a comeback, despite the collapse of its self-declared caliphate in Iraq and Syria several years ago.
McCallum said that "after a few years of being pinned well back, they've resumed efforts to export terrorism," and cited a March attack that killed more than 140 people at a Moscow concert hall and was claimed by IS, as "a brutal demonstration of its capability."
MI5 has faced criticism for its failure to stop deadly attacks, including a 2017 suicide bombing that killed 22 people at an Ariana Grande concert in Manchester.
"The first 20 years of my career here were crammed full of terrorist threats," McCallum said. "We now face those alongside state-backed assassination and sabotage plots, against the backdrop of a major European land war."
MI5, he said, "has one hell of a job on its hands."
