Royal Mail Ship

Royal Mail Ship (RMS) is the ship prefix used for seagoing vessels that carry mail under contract to the British Royal Mail.
History.
In the early 19th century, the British Admiralty provided RMS service.
The designation "RMS" has been used since 1840.
In 1850 contracts were awarded to private companies. Having the title "RMS" was seen as a mark of quality and a competitive advantage, because the mail had to be on time.