The sinister reach of Iran's Islamic Revolutionary Guard: Calls for UK to ban Iranian military wing as a terror group - as fears rise over Tehran-backed cells after latest arrests

Experts have also warned that some Iranians who come to study at British universities as international students on state scholarships are also spies. Kasra Aarabi, of the United Against Nuclear Iran think-tank, said IRGC recruiters did not focus on hiring British Iranians, who are usually secular and oppose the Ayatollah regime. But British Shias who originated from Pakistan, Iraq and Lebanon were targeted at the Arbaeen festival in the holy Iraqi city of Karbala, which attracts up to 20 million pilgrims a year.