It has long been the convention that the Sovereign of the day would approve the issue of home comforts to troops in the field at times of celebration, Christmas or New Year being the most common.
This tin contains a slab of chocolate that, incredibly, remains uneaten, although it would take a brave person to sample it today!
This particular treat was issued for New Year 1900. Modern variants of these gift packages contain games and pastimes as well as sweets and other useful knick-knacks.