Police correspondence files, case files and administrative files

From around the 1920s onwards, many types of record previously kept in book form began to be kept in series of files (normally lever arch files to begin with, and, later, modern cardboard files). Memoranda, circulars and so on were kept in administrative files. Correspondence files, including letters in and copies of letters out, replaced letter books. Case investigation files replaced, to some extent, the case/information books kept by individual stations or headquarters. However, although large series of administrative, correspondence and case files survive for many local and central government bodies, the equivalent records for police forces are generally no longer extant or are otherwise not available for public use. Among the records of Glasgow City Constabulary deposited with Glasgow City Archives, for example, only one case file survives: SR22/42/1 Report re murder of Constable James Campbell, 18 Jan 1919. Research using correspondence files is among the most time-consuming and unrewarding, except perhaps to the most dedicated of police historians and academic historians. The general paucity of case files is invariably a disappointment to journalists and local historians.