China plans to expand a ban on the use of iPhones in sensitive departments to government-backed agencies and state companies, a sign of growing challenges for Apple in its biggest foreign market and global production base. Several agencies have begun instructing staff not to bring their iPhones to work, people familiar with the matter said. In addition, the sources said Beijing intends to extend that restriction far more broadly to a plethora of state-owned enterprises and other government-controlled organisations. Several Chinese government agencies have begun instructing staff not to bring their iPhones to work. Bloomberg If Beijing goes ahead, the…