MI5 Chief Says Agency Devotes More Resources to State Threats Than During Cold War

MI5 Director General Ken McCallum said on 13 October 2026 that the agency is devoting more resources to countering state threats than it did during the Cold War. State threats have quadrupled over the past decade and now operate at roughly the same scale as counterterrorism work. Russia remains the primary aggressor, while Iran has shifted toward harder targets including military sites.

McCallum delivered the assessment in his annual speech at Thames House in London. He described Russia as “aggressor number one.” Moscow has avoided conventional conflict with NATO and instead uses hybrid tactics to unsettle European countries while its advances in Ukraine remain limited and costly. These methods include cyber operations, recruitment of criminal proxies, and attempts to disrupt energy and logistics infrastructure. McCallum said AI is supercharging the cybersecurity contest between attackers and defenders and could aid terrorists in developing bioweapons or new pathogens.

On Iran, McCallum reported more than 50 arrests linked to Iranian operations in the United Kingdom over the past year. Many targeted Jewish communities and sites. A notable shift in 2026 has been Iranian efforts to strike harder targets such as military installations. Prime Minister Andy Burnham has said Tehran was “highly likely” behind a suspected plot against RAF Fairford, an airbase used by US bombers. McCallum said the Fairford incident was not unique and that similar attempts have occurred elsewhere. Iran typically relies on criminal proxies rather than sophisticated direct operators, which limits the complexity of attacks it can mount on British soil.

The combined state-threat and terrorism workload marks a structural change for MI5. McCallum called it a huge shift from earlier periods when counterterrorism dominated. China is also listed among states of concern, though McCallum’s remarks focused on Russia and Iran. The agency has established specialized assessment centers for hybrid threats. Essential services such as banking, aviation, and healthcare face disruption risks from these campaigns.

McCallum cautioned against exaggerating the capabilities of adversaries who often outsource work to criminals. Their effectiveness depends on the sophistication of those intermediaries. Russia and Iran both deny involvement in hostile acts on British territory. British authorities have not released full details of the 50 arrests or the status of the Fairford investigation.

The speech comes amid ongoing European concerns about sabotage, arson, and cyber incidents attributed to Russian networks. Iranian activity has intensified against Jewish targets and, more recently, against military facilities. McCallum said the current threat environment is not a temporary blip. MI5’s resource allocation reflects that assessment. Further operational details remain classified.

The director general’s remarks provide the clearest public measure yet of how state threats have grown relative to traditional terrorism work. They also highlight the role of AI in both offensive and defensive capabilities. No specific new plots beyond those already reported were disclosed in the speech.