Aysu Biçer
13 October 2026•Update: 13 October 2026
The UK is facing a growing threat from extreme right-wing terrorism, with cases involving anti-immigration and anti-Muslim grievances increasingly escalating into terrorist intent, the head of British domestic intelligence service MI5 said Tuesday.
Delivering his annual address at MI5 headquarters in London, Sir Ken McCallum said extreme right-wing terrorism tends to "skew young" and is driven by online activity.
He added that al-Qaeda and ISIS (Daesh) "continue to direct and inspire attacks” while the increased threat is also driven "in significant part" by extreme right-wing terrorism.
"Over the last year the most marked trend has been an increase in cases where extremist versions of anti-immigration and anti-Muslim grievance are tipping into terrorist intent," he said.
He also disclosed that MI5 had recently investigated a "radicalized extreme right-wing 13-year-old here in the UK.”
"That investigation generated insight that enabled one of our international partners to prevent a lethal attack on their soil," he said.
Russia remains 'aggressor number one'
He said MI5 is devoting more resources to countering state threats than during the Cold War, warning that threats from foreign adversaries have quadrupled.
Russia remains "aggressor number one," he said, adding that the service’s operational missions against terrorism and state threats are now "pretty much of equal scale."
He also warned of growing "threats from Iran,” extreme right-wing terrorism, and the potential use of artificial intelligence (AI) by extremist groups to develop bioweapons.
McCallum said Russia is waging "hybrid warfare" against the UK and other European countries while avoiding actions that could trigger a joint response from NATO.
It would be “foolish” for the Kremlin to cross that line, he warned.
According to McCallum, Russia has stopped short of "conventional conflict" and instead seeks to destabilize European countries, while its progress in its full-scale invasion of Ukraine remains "minimal and horrifically costly."
He said MI5’s efforts to identify and expel Russian spies have weakened Moscow’s covert operations in the UK, forcing it to rely increasingly on criminal proxies to carry out attempted attacks.
"With its traditional covert footprint eviscerated by almost 1,000 expulsions since the invasion, the Kremlin's global toolkit is weak. So we see them scrambling to pay criminals to do their bidding," McCallum said, referring to the years since February 2022, when the Ukraine war began.
"These are not the actions of a great power with the strategic upper hand," he added.
McCallum also warned that Iran is expanding its hybrid campaign in the UK, saying MI5 had made more than 50 arrests over Iranian-linked activities in the past year.
AI poses emerging security risks
"We've caught terrorists seeking to exploit AI to improve their reconnaissance and attack methodologies, with AI-enabled drones adding a new twist," said McCallum.
He identified the potential use of AI by violent extremist groups to develop bioweapons as his greatest concern in this area.
Although the threat was "not yet realized,” McCallum warned that the technology has the "potential to change the stakes on existing or even new bioweapons."
"These risks are real. The UK Intelligence Community – MIS, GCHQ, M16 – is working closely with the UK's globally respected AI Security Institute to take them on," he said.
