RN Sub Lieutenant Rank Insignia
|Service branch||Royal Navy|
|Next higher rank||Lieutenant|
|Next lower rank||Midshipman|
Sub-Lieutenant is the lowest commissioned rank in the Royal Navy, excluding those commissioned from the "Lower Deck". Midshipmen, having completed their many years of training in the naval colleges and training ships, were promoted to the rank of Sub-Lieutenant, which was senior to the rank of 2nd Lieutenant and equal to a Lieutenant in the British Army.
The title of Sub-Lieutenant was substituted for that of Masters Mate by Order in Council of 16 April, 1861. At that time a Sub-Lieutenant ranked with a Lieutenant in the British Army. Until 1955 it was a rank of the Military Branch of the Royal Navy
- The Navy List (January, 1862). p. 285.