UK in ‘new era of national security’ as AI supercharges rising threats, security chief warns

By Issy Ronald, Nick Paton Walsh, CNN

London (CNN) — The United Kingdom has entered a new phase of national security as a “more contested era” replaces the stability of the post Cold War years, the head of the domestic security service MI5 said Tuesday, warning that threats from states and terrorists could be supercharged by artificial intelligence.

Ken McCallum called on Britain to be more resilient and vigilant, warning that the country faces a “new era of national security” as it fends off hybrid threats from a triumvirate of hostile foreign states – Russia, Iran and China.

“These days our terrorism and state threats operational missions are pretty much of equal scale; that in itself is a huge shift across recent years,” he said in his annual speech outlining threats facing the UK.

Those threats can take many forms, including “arson, sabotage, cyber-attacks, coercion (and) violence,” McCallum said.

AI is “already supercharging” some of these threats, especially in cybersecurity, McCallum said as he announced the creation of a new AI Threat Assessment Center. The technology could also strengthen the capabilities of “comparatively low sophistication actors” if governments don’t place sufficient “guardrails” around it,” he warned. Most worryingly, AI has the potential to help make destructive bioweapons, though this has not yet been realized, he added.

McCallum emphasized – echoing warnings from previous years – that the threat posed by states is now a key focus for the service. “You might be surprised to know that in 2026, MI5 is devoting more resource to countering state threats than during the Cold War,” he said. “Over the last decade, our state threats caseload has quadrupled.” He warned the new heightened threat environment was not a “temporary blip.”

Of these states, “Russia remains aggressor number one,” McCallum said, pointing to Moscow’s escalating campaign of “hybrid warfare” targeting European countries. He gave as examples a cyber attack on Polish energy infrastructure and an attempt to “use an explosive-laden drone to destroy a cargo plane in Germany.”

In the UK, “a man was charged last month under the National Security Act for allegedly preparing to sabotage a drone factory in Swindon,” McCallum added.

Still, these are not “the actions of a great power with the strategic upper hand,” McCallum said, noting that Russia’s capacity for espionage has been greatly weakened since more than 1,000 of its foreign staff have been expelled from their host countries since Moscow launched its full-scale invasion of Ukraine in 2022. Instead, Russia has scrambled “to pay criminals to do their bidding,” McCallum said.

Iran has used similar methods in an attempt to “expand their hybrid campaign,” he added. More than 50 people have been arrested in connection with Iran-linked plots, mostly directed against British Jewish communities, he said.

McCallum also referenced “Iranian ambitions to come at harder targets, like military sites,” alluding to the incident at RAF Fairford last month. He refused to provide further detail due to ongoing investigations but called the Fairford incident “not unique.”

“There have been other examples, not just in the UK, but around the world,” he added.

Britain’s Prime Minister Andy Burnham has said Iran’s Islamic Revolutionary Guard Corps was “almost certainly” responsible for directing a suspected plot to target the UK airbase used by US forces. Several senior Iranian officials have vehemently denied these accusations. Several men, including a British-Iranian dual national, were arrested in connection with the plot before being released on bail.

Shortly after the incident, the US made the unusual decision to move all its long-range bombers stationed in the UK back to their home bases on American soil following an unspecified new threat.

McCallum also accused China of conducting espionage in the UK, referencing an alert MI5 issued to the academic community two weeks ago and a case earlier this year which yielded the “first ever convictions for national security offences” connected to Beijing.

While he emphasized the increasing role of states, he noted that terrorism “remains a top concern for MI5” and that an “attack is highly likely.”

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