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

MI5 is now allocating more resources to countering state threats than it did at any point during the Cold War, according to the head of the UK's domestic intelligence service, in a stark assessment of how foreign aggression and emerging technologies are transforming the nature of national security.

In his annual address delivered at MI5's headquarters in central London, Sir Ken McCallum revealed that the volume of threats posed by foreign adversaries has quadrupled over the past decade. Russia was singled out as "aggressor number one," while Iran-linked activity targeting Jewish sites and military installations across Britain has also intensified sharply.

The intelligence chief described Russia as being engaged in hybrid warfare — a term encompassing cyber-attacks, sabotage and disinformation campaigns designed to destabilise adversaries without resorting to direct military confrontation. Rather than risking open conflict with Nato, Moscow is attempting to unsettle European nations, he explained, while its full-scale invasion of Ukraine has delivered only "minimal and horrifically costly" gains.

Sir Ken disclosed that almost 1,000 Russian operatives have been expelled from the UK since the invasion of Ukraine began, effectively dismantling the Kremlin's traditional covert presence on British soil. This, he argued, has forced Moscow into a position of dependence on paid proxies and criminals to carry out attempted attacks — behaviour he characterised as inconsistent with a great power holding the strategic advantage.

His remarks come amid mounting anxiety across Europe, where a growing number of leaders have publicly cautioned that Russia may be preparing provocative attacks intended to test their resolve in continuing to support Ukraine. The MI5 chief's assessment adds significant weight to those concerns, suggesting that hostile activity is not confined to the battlefield but extends into the domestic affairs of Nato member states.

Turning to Iran, Sir Ken revealed that approximately 50 arrests have been made in the past year in connection with Iran-linked activities. Much of this aggression has been directed at Jewish communities, he said, though Iranian operatives have also targeted what he described as "harder targets, like military sites." He referenced an incident at RAF Fairford in Gloucestershire, where three suspicious vans were discovered parked near the airbase. Seven people were arrested and subsequently bailed by counter-terrorism police. Although he did not address the incident directly in his speech, he told reporters afterwards that it was "not unique," adding that Iranian interest extends beyond that single location. Prime Minister Andy Burnham has previously stated that the incident was "almost certainly directed by Iran's Islamic Revolutionary Guard."

The MI5 director general issued a defiant message to those seeking to sow chaos on British streets, declaring that "hired thugs here or their paymasters overseas" would face an "unflinching response." He also noted that the National Security Act, legislation introduced in 2023 to target individuals acting on behalf of foreign powers, is being used extensively and has proven valuable in addressing threats from China as well as Iran and Russia.

A significant portion of Sir Ken's address focused on artificial intelligence, which he said is "supercharging the cyber-security contest between attackers and defenders." He warned that AI enables the production of propaganda and radicalising material tailored to individual targets, and confirmed that MI5 has intercepted terrorists attempting to exploit the technology to enhance their reconnaissance and attack methodologies. The integration of AI with drones, he added, represents "a new twist" in the evolving threat landscape.

Perhaps most concerning was his warning about the potential for extremist groups to misuse AI in developing biological weapons. While he stressed that this threat is "not yet realised," he cautioned that the technology has the "potential to change the stakes" fundamentally. He emphasised that the UK Intelligence Community — comprising MI5, GCHQ and MI6 — is collaborating closely with the UK's AI Security Institute to confront these dangers.

Reflecting on the unprecedented nature of the challenge, Sir Ken told his audience at Thames House that human history offers no precedent for confronting an actor more intelligent than humanity itself. To address this gap, he announced the establishment of an AI Threat Assessment Centre, which will evaluate sources and, in his words, "separate the bluster from the realities" of the rapidly evolving technological threat.

The MI5 chief also highlighted the continuing danger posed by extreme right-wing terrorism, noting that Islamist groups remain a serious concern as well. In April, the UK's terrorism threat level was elevated to severe for the first time in five years, indicating that an attack is considered highly likely. Sir Ken observed that counter-terrorism work and efforts to counter state threats are now "pretty much of equal scale" — a "huge shift" that reflects the broadening spectrum of dangers facing the country.

Addressing the contentious issue of Russian interference in the 2016 Brexit referendum, Sir Ken said it was "not new news" that Moscow had attempted to exert influence, though he drew a careful distinction between "interference attempted" and "outcome achieved." He acknowledged that Russian media outlets, troll farms and bot networks had sought to shape the debate, but stressed that the result of the referendum itself is "not in dispute." He expressed anxiety about the ongoing public discussion, warning that exaggerating the power of such operations risks "playing into our adversaries' hands by making these trolls look 10ft tall."

The speech paints a picture of a security environment in which traditional espionage, state-sponsored hybrid attacks, terrorism and emerging technologies converge. With Russia and Iran actively probing Britain's defences and AI introducing unpredictable new dimensions to both cyber and physical threats, MI5 finds itself navigating a landscape that Sir Ken's own remarks suggest is more complex and more dangerous than anything the service has confronted before.