MI5 Chief Warns UK Faces ‘New Era’ of Rising Threats from State Actors and Terrorists

Published: October 17, 2025, 21:40 EDT

The United Kingdom is confronting what intelligence officials describe as a “new era” of national security challenges, with rising threats from hostile foreign governments and extremist networks alike. MI5 Director General Ken McCallum said in his annual address that investigations into individuals potentially working for foreign states have surged by more than a third in the past year.

MI5 Reports 35% Rise in State-Linked Threats

In a wide-ranging briefing on Thursday, McCallum said MI5 has experienced the most significant shift in its mission since the 9/11 attacks. “A more hostile world is forcing the biggest changes in MI5’s mission since 9/11,” he told reporters. “Our teams are currently running near-record volumes of investigations.”

According to McCallum, the agency has seen a 35% year-on-year increase in the number of people under investigation for suspected involvement in activities on behalf of hostile foreign powers. The surge reflects what he called “a more confrontational international environment,” driven by Russia, China, and Iran — nations he identified as the “dominant trio” of state-based threats to British security.

Tribute to Manchester Victims and Rising Domestic Threats

Opening his speech, McCallum expressed condolences to the families of two people killed in a recent ISIS-linked attack on a synagogue in Manchester earlier this month. He said the tragedy underscored the “aggregate scale of the terrorist threat,” describing it as “huge” and increasingly diverse.

He noted that terrorist plots now stem from a complex mix of ideologies — including Islamist extremism, far-right radicalization, and other fringe movements — sometimes involving teenagers or individuals with mental health struggles. “We are in a new era,” McCallum said, “where state threats and terrorist risks coexist and sometimes intertwine.”

Espionage and Sabotage: From Cyberattacks to Arson

The MI5 chief cited several examples of foreign interference and espionage within the UK. Recent incidents include Chinese influence operations targeting Parliament and Russian-directed arson attacks against warehouses supplying military aid to Ukraine.

McCallum said that more than 20 potentially lethal Iran-backed plots were identified and disrupted in the past year alone. These plots targeted dissidents and individuals linked to opposition groups operating on British soil.

“The activities we’re tracking range from arson and sabotage to detailed intelligence gathering,” McCallum explained. “The only logical purpose of some of these efforts would be to make it feasible for someone to inflict harm — possibly lethal harm — on specific targets.”

Russian Spy Network Uncovered in London

McCallum’s remarks followed several high-profile prosecutions linked to espionage in Britain. In May, Orlin Roussev, 47, was sentenced to nearly 11 years in prison for leading a Russian spy ring operating out of the UK.

According to British prosecutors, Roussev and five other Bulgarian nationals conducted surveillance and collected intelligence for the Kremlin. The group gathered detailed information on journalists, dissidents, and Ukrainian soldiers training at a U.S. military facility in Germany.

While investigators determined the ring acted for financial gain rather than under direct orders from Russian intelligence, McCallum hinted that Moscow may be relying increasingly on proxy operatives. “I am able legally to say,” he remarked, “I don’t think it’s a good career move to work for the Russian Intelligence Services in the United Kingdom.”

Artificial Intelligence: Tool and Threat

McCallum also addressed the growing role of artificial intelligence (AI) in both strengthening and endangering national security. He said terrorist groups have already attempted to exploit AI for propaganda, weapons research, and target reconnaissance, though he warned against “hype and scaremongering.”

“I am not forecasting Hollywood movie scenarios,” McCallum said. “Artificial intelligence may never ‘mean’ us harm. But it would be reckless to ignore the potential for it to cause harm.”

He added that AI technologies could also provide significant benefits in intelligence gathering, analysis, and the early detection of emerging threats, offering opportunities to bolster the UK’s defenses if managed responsibly.

A Shifting Security Landscape

Analysts say the combination of state-backed espionage, terrorism, and technological vulnerabilities marks one of the most complex threat environments the UK has faced in decades. A senior security official quoted by Reuters said MI5 is now operating in “a hybrid security era,” where traditional intelligence operations merge with digital espionage and influence campaigns.

McCallum emphasized that MI5’s mission is expanding to meet these modern challenges. “The lines between physical and cyber threats are blurring,” he said. “Our job is to stay one step ahead — protecting the public from those who seek to undermine our democracy and safety.”

The MI5 director concluded by urging vigilance among government institutions, businesses, and the public, noting that national resilience depends on awareness and cooperation. “In a world of shifting alliances and new technologies,” he said, “our adversaries are adapting. We must do the same.”