MI5 chief warns AI could help terrorists design bioweapons while state threats hit Cold War levels.
During his annual threat briefing at Thames House in 2026, Sir Ken McCallum, director-general of MI5 painted a stark picture of Britain’s security landscape. He announced that the agency’s caseload of state-sponsored threats has quadrupled over the past decade, forcing MI5 to allocate more resources to counter-intelligence than it did during the Cold War.
AI Threat Assessment Centre launched to curb emerging dangers
Central to the speech was the unveiling of the AI Threat Assessment Centre (AITAC). This specialised unit, created in partnership with the UK’s AI Security Institute will monitor how hostile actors might misuse artificial intelligence.
Sir Ken warned that while the full scale of the risk remains unseen, AI could “change the stakes on existing or even new bioweapons.” He stressed that such scenarios are not speculative; “these risks are real” he declared.
The director-general highlighted several concrete incidents: terrorists have already attempted to merge AI with drone technology, and there are ongoing investigations into plots to weaponise biological agents using AI-generated instructions.
MI5, alongside GCHQ and MI6, is therefore intensifying its effort to establish robust guardrails that prevent low-sophistication actors from accessing dangerous knowledge.
State adversaries intensify hybrid campaigns
Sir Ken identified Russia as “aggressor number one,” noting that Moscow continues to pursue a hybrid-war strategy aimed at unsettling European nations while its conventional gains in Ukraine remain “minimal and horrifically costly.” Following nearly 1,000 expulsions of Russian operatives since the invasion, the Kremlin is allegedly recruiting criminal proxies and naïve volunteers to execute attacks on British soil.
Iran was also singled out for expanding a “sub-contracted” campaign that targets Jewish communities and, increasingly, hard-line government sites. Over the last twelve months, British authorities have made more than 50 arrests linked to Iranian-backed operations, including the arson of four Hatzola ambulances in Golders Green by an IRGC-aligned group. While the speech did not name the recent RAF Fairford plot directly, Sir Ken alluded to Iranian involvement in attacks on military installations.
China remains a persistent threat, with MI5 reporting ongoing espionage, coercion, and attempts to interfere with democratic processes. Just weeks earlier, an espionage alert warned that a front-group was funneling funds into AI-related research projects, a tactic designed to harvest cutting-edge technology for hostile purposes.
Extremism on the far right and Islamist fronts
Domestic terrorism continues to demand attention. Although the leadership of the Islamic State has been eroded, both ISIS and Al Qaeda still inspire attacks. More alarming, according to Sir Ken, is the rise of extreme-right terrorism, which has pushed the UK’s threat level to “severe” for the first time in five years. Anti-immigration and anti-Muslim rhetoric is increasingly translating into violent intent, often amplified by polarising online algorithms.
The director-general cited the murder of former MP Ann Widdecombe as a vivid illustration of the growing danger. A teenager with right-wing extremist leanings was also investigated, providing intelligence that helped an overseas partner foil a lethal plot.
Call for societal resilience and public participation
Concluding his address, Sir Ken appealed directly to citizens, framing national security as a shared responsibility. He outlined three pillars of resilience: safeguarding critical infrastructure, fostering community cohesion, and strengthening technological defenses. “When you hear ‘national security,’ think of the power grid flickering in your neighbourhood, the security upgrades at your local place of worship, or the manipulative posts that surface on social media feeds,” he said.
By urging the public to stay vigilant and report suspicious activity, MI5 hopes to create a “whole-of-society” shield against the sophisticated threats posed by state actors and AI-enabled extremists.
