Four individuals have been arrested in the United Kingdom on suspicion of assisting the Iranian intelligence service, prompting renewed warnings about the scale of hostile Iranian activity on British soil.

In response to the arrests, Alan Mendoza, director of the Henry Jackson Society, said the operation highlights what he described as a “real and persistent threat” from the Iranian regime.

“Today’s counter-terrorism arrests highlight the real and persistent threat posed by hostile Iranian activity on British soil,” Mendoza said. He argued that Iran has a long history of using “surveillance, intimidation and proxy networks” within Britain to pursue targets including dissidents and Jewish communities.

Mendoza said the arrests demonstrate the effectiveness of British security services in disrupting alleged Iranian activities before they escalate into violence. However, he also warned that the frequency of such interventions is concerning.

“The good news is that our security services are disrupting Iranian activity before it turns deadly,” he said. “The bad news is how often they are having to do it.”

He also described Iran as the world’s leading state sponsor of terrorism and warned that the country has repeatedly shown a willingness to conduct operations far beyond the Middle East.

While acknowledging that the investigation must be allowed to proceed, Mendoza said the UK should not underestimate the reach of a hostile state prepared to carry out intelligence or potentially violent operations inside its borders.

“Given Iran is involved in hostilities with our allies there should be a firm and kinetic response to this latest attempt by the regime to commit hostilities in the UK,” he added.

Authorities have not yet released further details about the suspects or the nature of the alleged assistance to Iranian intelligence. The investigation is ongoing.