MI5 Chief: UK Faces Greater State Threats Than Cold War

Sir Ken McCallum, head of Britain's domestic intelligence agency MI5, warned that the UK is now allocating more resources to counter state threats than during the Cold War, citing escalating activities from Russia, Iran, and China. Speaking at MI5's headquarters in London on October 13, 2026, McCallum labeled Russia "aggressor number one" and described its strategy as hybrid warfare designed to destabilize European countries while carefully avoiding direct NATO conflict.

McCallum noted that threats from foreign adversaries have quadrupled over the past decade, with MI5's terrorism and state threats operational missions now roughly equal in scale. He emphasized that Russia's strategy relies on destabilization rather than conventional military action, particularly as its full-scale invasion of Ukraine has achieved "minimal and horrifically costly" progress. Following the expulsion of nearly 1,000 Russian spies from the UK since Russia's invasion of Ukraine, the Kremlin has become dependent on paying criminal networks and proxies to carry out operations, McCallum stated.

Iran also poses a significant and expanding threat, McCallum warned, with 50 arrests in the past year linked to Iranian activities. Much of this aggression targets Jewish communities and military sites, he noted, referencing broader hybrid campaigns across Europe. Separately, McCallum highlighted the emerging risks posed by artificial intelligence, including its use in cybersecurity attacks, propaganda generation, and potential bioweapon development. MI5 has identified terrorists attempting to exploit AI for reconnaissance and attack planning, including AI-enabled drone operations, he said. In response, MI5 has established an AI Threat Assessment Centre to evaluate emerging threats.

The intelligence chief also warned of rising threats from extreme right-wing terrorism, noting that the UK's terrorism threat level was raised to severe in April 2026 for the first time in five years, meaning an attack is highly likely. McCallum invoked the National Security Act, a 2023 law targeting people working against UK interests for foreign powers, which has been used to tackle threats from China, Iran, and Russia. He stressed that the UK Intelligence Community—including GCHQ and MI6—is working closely with the AI Security Institute to address emerging AI-related security risks.