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

MI5 is allocating more resources to countering state threats than it did during the Cold War, Director General Ken McCallum said in his annual speech on 13 October. He stated that the agency’s caseload on hostile-state activity has quadrupled over the past decade and is now roughly equal in scale to its counter-terrorism work.

McCallum identified Russia as “aggressor number one.” He described Moscow’s use of hybrid tactics that stop short of conventional conflict, including the recruitment of criminal proxies after the expulsion of intelligence officers. Iran, he said, has made a “major shift” this year toward harder targets such as military sites. More than 50 people have been arrested in Iran-linked operations in the United Kingdom over the past year. Many of those operations targeted Jewish communities; others involved suspected plots against bases.

Prime Minister Andy Burnham said an incident near RAF Fairford in Gloucestershire was “almost certainly” directed by Iran’s Islamic Revolutionary Guard Corps. McCallum declined to comment on the specific case because of the ongoing investigation but noted that the Fairford episode was not unique. He added that Iran’s capability inside Britain is limited by the sophistication of the criminal proxies it hires.

Artificial intelligence, McCallum warned, is “supercharging the cyber-security contest between attackers and defenders.” He expressed particular concern that terrorists could use AI to develop bioweapons or new pathogens, and that the technology could be integrated with drones. Extreme right-wing terrorism also remains a rising threat, he said.

The speech was delivered at MI5 headquarters in London. McCallum called the present environment a “new era of national security” that is not a temporary blip. Essential services including banking, aviation and healthcare face disruption risks from state actors. The National Security Act 2023, which criminalises certain activities carried out on behalf of foreign powers, is being used extensively against Iran, Russia and China-linked cases.

Russia and Iran both deny involvement in hostile acts on British soil. McCallum’s figures place state-threat work on a par with counter-terrorism for the first time in the modern era of the service. The quadrupling of the caseload occurred against a background of reduced conventional intelligence presence after mass expulsions and a corresponding increase in the use of third-party criminals.

For Britain’s Jewish communities, the combination of Iranian-directed plots and domestic extreme-right activity has produced a sustained period of elevated threat. For military bases, the shift McCallum described implies that facilities previously considered lower priority now require additional protective resources. The speech did not include quantitative data on the number of plots disrupted or the precise resource split between the two mission areas.

McCallum’s remarks align with similar assessments from European partners that hybrid campaigns have expanded since the full-scale invasion of Ukraine. Whether the resource reallocation will continue to grow, or whether it has already reached a plateau relative to counter-terrorism, will become clearer in subsequent annual statements. The immediate operational picture is one of concurrent pressure from state proxies and domestic terrorism, with AI adding new technical variables on both sides.