The British Government codified this, to some extent, with the publication of the Official Secrets Act in 1889 and by the time of the First World War multi-tier classification systems were used to communicate information to and from various fronts.
The British Government codified. This multi-tier classification systems were used to communicate information to and from various fronts. This was to some extent and by the time of the First World War. This was with the publication of the Official Secrets Act in 1889.