The Merchant Navy is the maritime register of the United Kingdom and comprises the seagoing commercial interests of UK-registered ships and their crews. Merchant Navy vessels fly the Red Ensign and are regulated by the Maritime and Coastguard Agency (MCA). King George V bestowed the title of “Merchant Navy” on the British merchant shipping fleets following their service in the First World War; a number of other nations have since adopted the title. Previously it had been known as the Mercantile Marine or Merchant Service, although the term “Merchant Navy” was already informally used from the 19th century.
https://en.wikipedia.org/wiki/Merchant_Navy_(United_Kingdom)
