The arrest of five men near RAF Fairford, the British air base used by American bombers in operations against Iran, has sharpened scrutiny of Tehran’s capacity to project asymmetric power deep inside Europe. But it has also demonstrated how quickly suspicion can run ahead of evidence. British authorities have not established any Iranian connection to the arrested individuals, all of whom have since been bailed, and Defence Secretary Wes Streeting has warned that it would be “very unwise” to spec
