MI5 Director General Ken McCallum said on Thursday that UK intelligence agencies were stepping up efforts to counter what he called mounting lethal plots by Tehran to silence dissidents on British soil.
"Iran's autocratic regime is ... frantically trying to silence its opponents around the world, including in the UK," he told reporters in a briefing.
"2025 has required us to grow our counter Iran effort," McCallum added. "MI5 has tracked more than 20 potentially lethal Iran-backed plots in just the one year since I last stood at this podium. The UK was among the first to call out this wave of Iranian transnational aggression. But we're far from alone."
The British government last month said it was determined to frustrate what it called escalating Iranian threats to people on UK soil, citing cyberattacks and the use of criminal proxies to carry out attacks.
Its statement came after a July 10 Parliamentary Intelligence and Security Committee on Iran which said Iran poses one of the gravest state-based threats to British national security, on par those from Russia and China.
"State threats are escalating. In the last year, we've seen a 35% increase in the number of individuals we're investigating for involvement in state threat activity," McCallum added, mentioning Russia and China as other key adversaries.
FBI Director Kash Patel said in a presentation to President Donald Trump and reporters in the White House on Wednesday that US law enforcement had stepped up arrests for Iran-backed espionage operations.
"The national security mission, Mr. President, under your leadership has never been stronger. We have gone after espionage activities against our main counterparts in China, Russia and Iran," he said.
"(On) Iran, we have had a 50% increase again in espionage cases."
