<p>The Case Information Database (CID) has been the source immigration case working system since 1998. Individual records of immigration status have therefore been digitised for the last 20 years. CID undergoes nightly back-ups to tape and has replication between the primary and secondary data centres.</p><p>There has been no systematic loss of immigration status records. Where any individual cases are identified or raised as having incorrect or incomplete records, these are treated as an absolute priority.</p>