The head of MI5 says Iran is trying to hit military sites in the U.K. and the suspected plot to attack a U.S.-run military air base in September is not unique. Ken McCallum, who leads the U.K.’s domestic security service, said Tehran is seeking to intensify its attacks in Britain beyond the traditional targets of Iranians opposed to the Islamic authorities. That has included arson and sabotage attacks on Jewish sites that Britain says were carried out by Iranian proxies. He says the incident at RAF Fairford is not unique and there have been other examples around the world.