A file of correspondence concerning the establishment and recruitment of staff for the British Code and Cypher School after the First World War. Subjects discussed in the letters include the role and responsibilities of the school; recruitment of personnel, including lists of staff and their salaries; the organisation and closure of listening stations; arrangements for the monitoring of telegraphic communications; arrangements to preserve the secrecy of the institution and security of British codes; the salaries of employees, and arrangements for the accommodation of the school.