MI5 Chief Warns Russia, Iran and AI Are Reshaping Britain's Security Threat

The head of Britain's domestic intelligence service has disclosed that MI5 now commits more resources to countering state threats than it did at any point during the Cold War, describing a dramatic reordering of national security priorities driven by hostile activity from Russia, Iran and the rapid spread of artificial intelligence.

In his annual address delivered at MI5's headquarters in central London, Sir Ken McCallum said the volume of threats emanating from foreign adversaries had quadrupled over the past decade. Russia, he declared, remains "aggressor number one," while Iran-linked aggression has escalated sharply, with much of it aimed at Jewish sites and military installations on British soil.

The MI5 director general characterised Moscow's approach as hybrid warfare—a term used to describe non-military methods such as cyber-attacks, sabotage and disinformation campaigns intended to pressure and destabilise an opponent. Such operations are frequently carried out through proxies, and Russia consistently denies involvement despite accumulating evidence to the contrary.

Sir Ken said Russia has deliberately avoided "conventional conflict" with Nato, opting instead to unsettle European nations while its full-scale invasion of Ukraine yields what he called "minimal and horrifically costly" progress. His assessment comes as a growing number of European leaders have publicly warned that Moscow may be preparing attacks designed to test their resolve in supporting Kyiv.

The intelligence chief highlighted a significant shift in the Kremlin's operational capacity, revealing that nearly 1,000 expulsions since the invasion of Ukraine have "eviscerated" Russia's traditional covert footprint. As a result, he said, Moscow's global toolkit has been weakened to the point where it is "scrambling to pay criminals to do their bidding"—behaviour he described as uncharacteristic of a great power holding the strategic upper hand.

Pressed after the speech on recent comments by Prime Minister Andy Burnham regarding Russian interference in the Brexit referendum, Sir Ken said attempts from Moscow were "not new news," though he drew a careful distinction between "interference attempted" and "outcome achieved." He acknowledged that Russian media outlets, along with "so-called internet trolls and bot farms," had sought to influence the Brexit debate, but stressed that the 2016 referendum result itself was "not in dispute."

The MI5 chief also expressed unease about the continuing public argument over Russian interference, telling reporters he was "a little bit anxious that we don't play into our adversaries' hands by making these trolls look 10ft tall." His caution reflects a broader intelligence community concern that amplifying the perceived reach of foreign influence operations can inadvertently magnify their effect.

Turning to Iran, Sir Ken revealed that authorities had made 50 arrests over the past year connected to Iran-linked activities, with a substantial portion of that aggression directed at Jewish communities. He added that Iranian operations had also targeted "harder targets, like military sites," extending beyond the incident at RAF Fairford in Gloucestershire, where three suspicious vans were found parked near the airbase and seven people were arrested and bailed by counter-terrorism police.

While the MI5 chief did not reference the RAF Fairford arrests directly in his prepared remarks, he told journalists afterwards that the episode was "not unique," stating: "We have seen Iranian interest beyond RAF Fairford in the UK." Prime Minister Burnham has previously said the airbase incident was "almost certainly directed by Iran's Islamic Revolutionary Guard."

Sir Ken issued a stern warning to those orchestrating such activity, declaring that "those who seek to cause mayhem on British streets—whether hired thugs here or their paymasters overseas—will meet an unflinching response." He also noted that the National Security Act, a 2023 law designed to prosecute individuals working against UK interests on behalf of foreign powers, is now in heavy use, having been deployed against threats from China as well as Iran and Russia.

On the subject of artificial intelligence, the MI5 chief offered a detailed assessment of how the technology is altering the threat landscape. He said AI can generate propaganda and radicalising material tailored to specific individuals, and confirmed that MI5 had "caught terrorists seeking to exploit AI to improve their reconnaissance and attack methodologies, with AI-enabled drones adding a new twist."

The most alarming long-term concern, according to Sir Ken, is the potential for extremist groups to harness AI in developing new and existing bioweapons. While he stressed that this danger is "not yet realised," he warned the technology has the "potential to change the stakes." He said the UK Intelligence Community—comprising MI5, GCHQ and MI6—is working closely with the UK's AI Security Institute to confront these risks.

Sir Ken framed the challenge in stark terms, telling his audience at Thames House: "Put at its simplest, human history has given us no experience of facing an actor which is smarter than we are." To address the unknown dimensions of the AI threat, he announced the creation of a new AI Threat Assessment Centre, which will evaluate sources and, in his words, "separate the bluster from the realities."

The speech also touched on the balance between terrorism and state threats, which Sir Ken said were now "pretty much of equal scale"—a "huge shift" in recent years. He noted rising threats from "extreme right-wing terrorism" alongside the persistent danger from Islamist groups, referencing the decision in April to raise the UK's terrorism threat level to severe for the first time in five years, meaning an attack is considered highly likely.

In a further observation on AI's role in the cyber domain, Sir Ken said the technology was "supercharging the cyber-security contest between attackers and defenders." His remarks underscore a growing consensus among Western intelligence agencies that AI is simultaneously a tool for enhancing national defence and a force multiplier for adversaries seeking to cause harm.

The wide-ranging address painted a picture of an intelligence service operating under sustained pressure on multiple fronts, from Russian proxy operations and Iranian-directed plots to technologically empowered terrorist networks. Yet Sir Ken's message also carried an element of reassurance: MI5's expanded focus on state threats, combined with new legal powers and emerging AI-focused capabilities, signals an agency actively adapting to a threat environment that shows no sign of easing.