Britain’s domestic security agency, MI5, has warned of a heightened threat from Iran, including a suspected plot to attack military sites on British soil, marking a significant shift in Tehran’s tactics. In his annual threat briefing on Tuesday, MI5 Director General Ken McCallum outlined concerns about an escalation in Iranian operations targeting both civilian and military locations across the United Kingdom.
The most immediate focus is an incident on September 27 near Royal Air Force (RAF) Fairford in Gloucestershire, a base previously used by U.S. bombers during operations against Iran. Police arrested seven men in connection with suspicious activity involving three vans near the base, where gasoline but no explosives were found. Authorities described the attempt as potentially a botched arson attack. Following the plot, the United States withdrew its bomber fleet from RAF Fairford, citing intelligence about possible Iranian-led threats, including a feared drone attack, although British officials have expressed skepticism about Tehran’s capacity to conduct a sophisticated drone operation within the U.K.
Prime Minister Andy Burnham addressed Parliament on Monday, stating that the plot was “highly likely” coordinated in Iran and "almost certainly" directed by the Islamic Revolutionary Guard Corps (IRGC), Tehran’s elite security force. He affirmed the government’s commitment to cracking down on Iranian criminal networks operating in Britain and to implementing further sanctions aimed at restricting the IRGC’s ability to conduct hostile activities abroad. Foreign Secretary Ed Miliband supported this stance, imposing targeted sanctions on two Iranian individuals alleged to be involved in coordinating attacks against British and international interests.
MI5 reported that more than 50 people have been arrested in the last year in connection with Iran-linked plots within the U.K., including two Iranian nationals charged this month over a suspected terrorist plan targeting Jewish communities in Manchester. McCallum noted a troubling trend of Iran-backed proxies conducting arson, sabotage, and attacks against Jewish sites, calling such acts “sickening.” These incidents have been linked to Iranian proxy groups such as Kataib Hezbollah and fronts like Harakat Ashab al-Yamin al-Islamiyya (Hayi), which have claimed responsibility for attempts in Britain and other European countries. British authorities describe these operations as generally unsophisticated and carried out by local recruits, sometimes unaware of who has recruited them.
McCallum emphasized that Iran’s ambitions appear to be evolving beyond attacking softer civilian targets to focusing on “harder targets, like military sites.” He cautioned that while Iran’s operations in the U.K. currently involve criminal proxies with limited capabilities, the IRGC possesses stronger operational capacities in regions closer to Iran, underscoring the risk of more sophisticated attacks.
The MI5 chief also highlighted a broader context of growing hybrid warfare threats to Britain’s national security from state actors, naming Russia alongside Iran and China as principal concerns. He pointed to Russia’s ongoing attempts to undermine support for Ukraine through covert activities across Europe, characterizing Moscow’s tactics as aggressive but relying on deniable proxies.
Addressing emerging technological risks, McCallum discussed the increasing role of artificial intelligence in security threats. He raised concerns about AI’s potential to facilitate new forms of bioweapons and cyberattacks, noting that MI5 has established a specialized AI Threat Assessment Centre to monitor and respond to these challenges.
Iran has denied involvement in the incident at RAF Fairford. Nevertheless, Britain and a coalition of 29 countries, including the United States, France, Germany, Canada, Australia, and New Zealand, have publicly condemned Iran’s use of violent attacks, including sabotage and cyber operations, attributing responsibility primarily to the IRGC and associated proxy groups.
The developments reflect a sharper confrontational stance between the U.K. and Iran amid heightened geopolitical tensions following ongoing conflicts involving the United States and Iran earlier this year. British authorities continue to monitor and respond to the evolving threat landscape, emphasizing a comprehensive approach that combines law enforcement, intelligence operations, and diplomatic measures.