Two suspected Iranian spies were arrested Thursday after attempting to enter Britain’s key nuclear submarine base at HM Naval Base Clyde in Faslane, Scotland.
Armed police detained a 34-year-old man, believed to be an Iranian national, and a 31-year-old woman outside the high-security site, which houses the UK’s nuclear deterrent submarines equipped with Trident missiles.
The Royal Navy said the pair “unsuccessfully attempted to enter HM Naval Base Clyde on Thursday 19 March” and confirmed the case is under investigation.
A defense source described the attempt as “unsophisticated,” but officials remain concerned the suspects may have been conducting surveillance or preparing for a potential attack.
According to security sources, the pair tried to drive into the base but were stopped by Ministry of Defence Police. They remained nearby in their vehicle and were said to be acting suspiciously before being arrested.
Sniffer dogs were deployed to search the vehicle for explosives, and the base was temporarily placed on heightened alert.
Police Scotland said: “Around 5 pm on Thursday, 19 March, 2026, we were made aware of two people attempting to enter HM Naval Base Clyde. A 34-year-old man and a 31-year-old woman have been arrested in connection and enquiries are ongoing.”
The incident comes amid heightened tensions as Iran faces sustained airstrikes by the United States and Israel, raising fears of retaliatory or asymmetric attacks targeting Western interests.
Former U.S. national security adviser John Bolton warned such threats are likely, saying: “We should all be on a heightened state of alert.”
“Given the pummelling the Iranians are taking, their resort to asymmetric warfare, particularly terrorist acts, is almost guaranteed,” he added.
Iran has also warned that countries supporting U.S. operations could be seen as participants in the conflict. Foreign Minister Seyyed Abbas Araghchi said: “We reserve our inherent right to defend the country’s sovereignty and independence.”
The Faslane base, located about 25 miles northwest of Glasgow, is one of the UK’s most sensitive military installations, home to Vanguard-class nuclear submarines and Astute-class attack submarines, both powered by nuclear reactors.
A major incident at the base could have severe consequences, given its role in Britain’s continuous at-sea nuclear deterrent.
The arrests come as separate espionage cases linked to Iran unfold in the UK. Earlier this month, two Iranian nationals appeared in court in London on suspicion of spying on Jewish and Israeli-linked targets, including the Israeli Embassy and a Jewish community center.
British intelligence has warned of a growing number of Iran-linked plots. MI5 Director General Ken McCallum said the agency had tracked “more than twenty potentially lethal Iran-backed plots in just the one year.”
Security incidents at HMNB Clyde have also increased sharply in recent years, rising from 16 in 2021 to 149 in 2022, according to official data.
The base is protected by Ministry of Defence Police and Royal Marines from the 43 Commando Fleet Protection Group, both of which were placed on heightened readiness following the incident.
Officials have not yet disclosed further details about the suspects or potential charges.