MI5’s director-general, Sir Ken McCallum, has warned that Russia, Iran and China have driven a marked rise in threats to the UK from foreign states. He told a speech at the service’s London headquarters that the number of people investigated for involvement in ‘state threat activity’ rose by 35% in the last year. The Security Service said it routinely uncovers plots from foreign states to carry out surveillance, sabotage, arson or acts of violence in Britain. It is also grappling with the ‘ever-present threat’ of terrorism, with a substantial number of children drawn into investigations. He noted that one-in-five of the 232 terrorism arrests last year were under-17.

Since the start of 2020, MI5 and the police have disrupted 19 ‘late-stage attack plots’ and intervened in ‘many hundreds of developing threats’. The director-general described a ‘new era’ for the service because of the combination of terrorism and rising state threats. ‘In 2025, a more hostile world is forcing the biggest shift in MI5’s mission since 9/11,’ he said. He warned of state-backed espionage ‘including against our Parliament, our universities, our critical infrastructure’. He added that foreign powers were using ‘ugly methods’ such as arson and violence.

Russia was described as ‘committed to causing havoc and destruction’ around the world. The director-general suggested that the expulsion of Russian spies from embassies across Europe had left Vladimir Putin’s intelligence services relying on ‘disposable’ proxies, often recruited online. ‘In the last year we and the police have disrupted a steady stream of surveillance plots with hostile intent, aimed at individuals Russian leaders perceive as their enemies,’ he said. ‘And we’re seeing Russia-based figures using online platforms in wider attempts, largely unsuccessful, to sow the seeds of violence, chaos and division here in the UK.’ Iran was ‘frantically trying to silence its opponents around the world’, with MI5 tracking ‘more than 20 potentially lethal Iran-backed plots’ in the last year. On China, the relationship is ‘by its nature complex’ but MI5 would ‘detect and deal, robustly, with activity threatening UK national security’.