This series contains files and record-of-service cards, detailing the service of officers in the Royal Navy, the Royal Naval Reserve, the Royal Naval Volunteer Reserve and the Women's Royal Naval Service (WRNS).
The Admiralty had traditionally recorded such information in books and registers, such as will be found in earlier ADM series. This new format - cards and files - was introduced early in the twentieth century for all officers then serving, including therefore some with service dating back to circa 1880 (and possibly earlier still in a few cases).
Duplicated and additional information on many of the male officers whose records appear in this series will therefore be found among the books and registers in the earlier ADM series as listed, ADM 240 especially.
Duplicated and additional information on some of the female officers (i.e. WRNS) whose records appear in this series may be found in the two series containing WRNS First World War officers' service records - ADM 318 and ADM 321.
Whereas so often an entry in a book or register would relate to only one period of an officer's service, the introduction of the individual record card/file brought in the concept of a single continuous record spanning the length of the officer's service. Some records in this series therefore detail service through both World Wars and into the 1950s.
Please Note: Electronic images of ADM 340/1-150 are available online.