U.K.’s MI5 Cites Growing Threats From Russia, China, Iran—and Right-Wing Extremists

LONDON—The head of the U.K.’s domestic intelligence service, MI5, said the agency is doubling the resources it devotes to tackling threats from Russia, China and Iran—and faces a growing challenge from right-wing extremists, many of whom are teenagers.

The shift of emphasis comes after 20 years of focus on Islamist terrorism has crowded out other priorities for the agency. Yet, MI5 Director-General Ken McCallum said, Islamist terrorism still constitutes the agency’s largest operational mission and new challenges could arise as the U.S. and its allies depart from Afghanistan.

Mr. McCallum said Wednesday that the agency faces daily threats and espionage activities that predominantly come “in quite varying ways from state or state-backed organizations in Russia, China or Iran” that have to be managed alongside U.K. efforts at engagement with all three countries.

The threats are against individuals, digital infrastructure and espionage that is focused on the government but also on universities and businesses, he said. He also cited efforts at disinformation and attempts to seek hidden relationships with public figures, “hack-and-leak operations” aimed at having a political impact and troll farms seeking to sow and deepen divisions in society.

Mr. McCallum said the agency had identified more than 10,000 disguised approaches by foreign spies on professional social-media sites that sought to manipulate people in the U.K. where people in high-tech businesses, scientific research and exporting businesses were all of interest to foreign spies.

It wasn’t clear how quickly the agency was proposing to double its resources focused on state threats. In the financial year ending in April 19, it reported 67% of its resources were devoted to international counterterrorism, 20% against terrorism related to Northern Ireland and 13% focused on counterespionage and other threats. Britain’s intelligence agencies don’t disclose their individual budgets.

The agency’s plans to shift toward challenges from other states have gone awry in the past. Mr. McCallum told reporters that MI5 had made a strategic decision to boost resources devoted to the activities of state adversaries after the London Olympics in 2012. “And then Syria happened,” he said.

The conflict there presented, he said, a terrorism risk of “unprecedented volume, scale and diversity,” which meant the agency wasn’t able to shift resources as planned.

After a televised speech in which he gave an annual assessment of MI5’s work, Mr. McCallum spoke off-camera to reporters, saying that the organization didn’t see a requirement to do less on counterterrorism, where it would try to make use of improved technology and any extra money provided by the government.

Mr. McCallum also depicted a growing threat from extreme right-wing terrorism, which his organization took over responsibility for just over a year ago. Federal Bureau of Investigations director Christopher Wray said earlier this year that domestic extremism was a growing threat in the U.S.

Mr. McCallum said one in five of U.K. counterterrorist investigations, excluding those in Northern Ireland, concerned right-wing extremists. Of 29 terrorist plots disrupted in their late stages in the past four years, 10 were extreme right-wing terrorism, he said.

He said that brand of terrorism frequently attracted teenagers, in one case one as young as 13, encouraged by an online environment of “extremist echo chambers” where thousands engaged in hate-filled rhetoric and claimed violent aspirations to impress each other. He said this made it difficult to determine which individuals among thousands might mobilize toward violence.

He said there wasn’t evidence of significant organization. “This is much more a desperate, almost cultlike phenomenon where you have atomized people across the internet,” he said.