Britain's domestic spy chief says "hybrid tactics" used by Russia and Iran are evolving. Here are some of the most notable incidents of 2026.F
London — The head of Britain's top domestic spy agency MI5, Sir Ken McCallum, painted a dark picture Tuesday of the changing national security threats facing the U.K. and the world.
"We have entered a new era of national security, requiring a new response," he said in his annual threat update at MI5 headquarters in London. "Those who mean the U.K. harm aren't attacking things government owns or controls … They're aiming at people, businesses, communities."
McCallum said that among state threats, "Russia remains aggressor number one," while intelligence analysts have also seen a "major shift" in "Iranian ambitions to come at harder targets."
Both countries, he said, have adopted more and evolving "hybrid tactics" as they target everything from air force bases to synagogues across the U.K. and Europe. Below is a look at some of the incidents that fit that description over the last year alone.
Iran has used and continues "using criminal proxies to try to intimidate oppositionists, Iranian media organizations, and Israeli sites," McCallum said.
But as the U.S. war with Iran nears the eight month mark, analysts have also seen the Iranian regime, "like Russia, attempting to expand their hybrid campaign," he said, leading to more than 50 arrests in the U.K. over the last year alone.
"Sadly, much of this aggression has been aimed at British Jewish communities," McCallum said, speaking of incidents this year that included "a wave of arson and sabotage incidents targeting Jewish communities in the U.K. and other European nations," but also acts targeting "harder targets, like military sites."
Many of these attacks were claimed by a group calling itself Harakat Ashab al-Yamin al-Islamiya (HAYI), or the Islamic Movement of the Companions of the Right, which U.K. authorities have sanctioned and said is tied directly to the elite Quds Force of Iran's Islamic Revolutionary Guard Corps, which Britain considers a terrorist organization.
A CBS News investigation in March found the group appeared to have links to Iran, and a member said it would "keep threatening U.S. and Israeli interests worldwide until we've avenged every child in Gaza, Iran, Lebanon, and the resistance nations … We urge people to stay away from Zionist and American interests and individuals to keep themselves safe."
For now, Russia remains the biggest threat to security, according to the U.K. spy chief's Tuesday briefing.
"The Russian military and intelligence services are once again escalating their attempts at hybrid warfare," McCallum said, adding that Moscow was "being careful to stay below the NATO Article 5 threshold" with its actions, which would trigger the alliance's collective defense principle.
"It'd be foolish for them to cross" that line, he said, and so far Russia "is using tactics that stop short – though sometimes not much short – of conventional conflict."
Incidents linked to Russia this year include: