U.K. Sees Myriad Domestic Threats, Mainly From Iran, Russia and China

LONDON — Iran has tried to kill or kidnap at least 10 critics based in Britain since the start of the year, the head of the British security service said on Wednesday as he underscored perceived threats from a diverse range of sources, including Russia, China and Islamist and far-right terrorists at home.

Giving an annual update of security risks to Britain, Ken McCallum, the director general of MI5, described Iran as the state actor that “most frequently crosses into terrorism,” and one willing to resort to violence to silence its opponents.

The disclosure followed assertions that two British-based journalists working for a TV station, Iran International, had been informed by London’s Metropolitan Police of threats to their lives. That disclosure prompted an official warning from Britain’s foreign ministry to Iran’s most senior diplomat in London.

But against the backdrop of the war in Ukraine and rising tensions with China, Mr. McCallum acknowledged that Britain’s intelligence services faced a challenge in setting priorities. For example, it must balance efforts to stop “teenage would-be terrorists radicalized in extreme right-wing spaces online” against protecting Britain’s “military secrets from Russian cyberhackers.”

The complexity of the multiple threats the country faces was, he said, “huge.”

Peter Neumann, a professor of security studies at King’s College London, said the increased activity from Iranian agents was most likely linked to concerns about the growing protest movement within the country.

He added that the range of threats cited by Mr. McCallum illustrated a change in the focus of British security services in recent years — away from Islamist terrorism toward a broader range of actors.

“You can feel the difference — that speech would not have been given in that way in 2020 or even 2021,” Professor Neumann said. “It has been a rapid shift, a real change,” he added, noting that while the threat from Islamist terrorism still persisted, it “feels like it has decreased a lot.”

Much of the speech, delivered at M15’s headquarters in London, focused on threats from Russia, whose aggression, Mr. McCallum said, would challenge Britain for years to come.

Western nations are responding, he said, noting that 600 Russian officials — of whom 400 were judged to be spies — had been expelled from Europe in what he called “the most significant strategic blow against the Russian intelligence services in recent European history.”

The scale of those expulsions, together with the rollout of Western economic sanctions designed to isolate Russia, had proved a surprisingly potent test for Russia’s president, Vladimir V. Putin, he added.

Well before Russia’s invasion of Ukraine, Britain was especially sensitive to the activities of Russian agents, and its pushback against Moscow’s spy networks intensified after the nerve agent poisoning of Sergei V. Skripal, the former Russian agent, and his daughter, Yulia, in Salisbury, England, in 2018.

Since that episode prompted Britain to expel 23 Russian diplomats on espionage grounds, it has refused 100 diplomatic visa applications from Moscow.

But Russia is continuing to use an extensive range of disruptive tactics, including cyberattacks, disinformation, espionage and interference in democratic processes. It has also sought to deploy the wealth of its oligarchs, many of them British based, to peddle influence.

Tensions with China have also increased lately. But in contrast to Moscow, Beijing appears to be playing a more subtle and strategic “long game,” Mr. McCallum said. Not only is it seeking to co-opt and influence Britain’s lawmakers across the political divide, but it is also cultivating contacts early in their careers in public life, hoping to build a debt of obligation to exploit later.

Nonetheless, opponents among the Chinese diaspora in Britain have been subject to the sort of harassment and coercion seen recently when a pro-democracy protester was attacked at the Chinese Consulate in Manchester. In that clash, the protester, a supporter of democracy in Hong Kong, said he was dragged inside the consulate grounds by masked men and then kicked and punched.

As for Islamist and far-right homegrown terrorism, the authorities have foiled 37 planned attacks since 2017, including eight in the past 12 months, the agency said.

Investigations of Islamist terrorism make up around three-quarters of the British security service’s terror-related caseload. Even relatively unsophisticated plots have proved deadly, including the fatal stabbing of the Conservative Party lawmaker David Amess in 2021 in Leigh-on-Sea, Essex, east of London.

Terrorism motivated by extreme right-wing ideology has continued to evolve away from structured groups toward a more diffuse online threat, Mr. McCallum said.

“From the comfort of their bedrooms, individuals are easily able to access right-wing extremist spaces, network with each other and move toward a radical mind-set,” he said.

Investigators have seen increased efforts among right-wing agitators to gain access to weapons, particularly firearms, including homemade or 3-D printed models.

“We are seeing growing numbers of right-wing extremist influencers, operating globally, fueling grievances and amplifying conspiracy theories,” said Mr. McCallum. “This problem feels like it will endure.”