UK enters new national security era as AI amplifies state and terrorist threats, MI5 chief warns

UK enters a new national security era

The United Kingdom has entered a new phase of national security, according to the head of its domestic security service MI5, Ken McCallum. He warned that a “more contested era” replaces the stability of the post Cold War years, declaring the country is entering “a new era of national security.” He also warned that Iran’s hybrid campaign includes efforts to target British Jewish communities and military installations.

State threats, AI amplification and emerging risks

McCallum said terrorism and state threats now operate on roughly equal scale, a shift he described as “a huge shift across recent years.” He listed the manifestations as “arson, sabotage, cyber-attacks, coercion (and) violence.” He noted that AI is “already supercharging” some of these threats, especially in cybersecurity, and announced the creation of a new AI Threat Assessment Center. He added that the technology also has the potential to help make destructive bioweapons, though this has not yet been realized. He expressed concern that “comparatively low sophistication actors may have a capability uplift in the AI era” if governments do not enact effective “guardrails” around the technology.

Resource shift and specific incidents involving Russia, Iran and China

McCallum emphasized that the threat from states has grown to eclipse the Cold War era, stating “You might be surprised to know that in 2026, MI5 is devoting more resource to countering state threats than during the Cold War,” and that “Over the last decade, our state threats caseload has quadrupled.” He identified Russia as the top aggressor, pointing to its escalating campaign of “hybrid warfare” targeting European countries through means such as a cyber attack on Polish energy infrastructure or an attempt to “use an explosive-laden drone to destroy a cargo plane in Germany.” In the UK, he said, “a man was charged last month under the National Security Act for allegedly preparing to sabotage a drone factory in Swindon.” He added that these actions are not those of a great power with a strategic upper hand, noting that Russia’s capacity for espionage has been weakened after more than 1,000 of its foreign staff were expelled from host countries since Moscow launched its full-scale invasion of Ukraine in 2022, and that Russia has instead scrambled “to pay criminals to do their bidding.” Regarding Iran, McCallum said it has used similar methods to “expand their hybrid campaign,” with more than 50 people arrested in connection with Iran‑linked plots, mostly directed against British Jewish communities. He 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.” He said there have been other examples, not just in the UK, but around the world.

China espionage, terrorism concerns and related developments

McCallum also accused China of conducting espionage in the UK, citing an MI5 alert to the academic community issued two weeks ago and a case earlier this year that yielded the “first ever convictions for national security offences” connected to Beijing. While he emphasized the growing role of state actors, he noted that terrorism “remains a top concern for MI5” and that an “attack is highly likely.” He quoted Britain’s Prime Minister Andy Burnham as saying Iran’s Islamic Revolutionary Guard Corps was “almost certainly” responsible for directing a suspected plot to target the UK airbase used by US forces, adding that several senior Iranian officials have vehemently denied these accusations and that 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 moved all its long‑range bombers stationed in the UK back to their home bases on American soil following an unspecified new threat.