British Jews face the greatest threat in their history, as police investigate an Iran-linked group claiming responsibility for a spree of antisemitic attacks, London’s top cop warned. “If you overlay three things now — hate crime, terrorism and hostile state activity — you add all that together, that combined effect with that building of ideology online, that is really dangerous and troubling,” Sir Mark Rowley, head of London’s Metropolitan Police, told The Times of London Friday. “Whether you’