Britain's domestic intelligence chief used his annual threat speech in London on Tuesday to deliver one of the starkest public warnings yet about state aggression, naming Russia the leading aggressor in an escalating campaign of hybrid warfare.
MI5 Director General Ken McCallum, speaking at the agency's Thames House headquarters, said Russia is conducting activity designed to stay below the threshold that would trigger a NATO response. With almost 1,000 Russian officials expelled from Western countries since the invasion of Ukraine, he said, Moscow's traditional intelligence footprint has weakened — pushing it toward volunteers and criminal proxies to do its work. MI5, he added, is now devoting more resources to countering state threats than it did during the Cold War.
Iran drew a parallel warning. McCallum accused Tehran of also working through criminal proxies in Britain; operations linked to Iran have produced more than 50 arrests in the UK, many connected to plots aimed at Jewish communities, alongside new interest in harder, military-linked targets. Both Russia and Iran deny conducting malign activity.
Artificial intelligence ran through the speech as a growing threat multiplier: attackers have been caught using AI for reconnaissance and attack planning, and McCallum flagged AI-enabled drones and the misuse of AI in bioweapon and pathogen development among the concerns at the top of MI5's agenda.
