High Quality Content by WIKIPEDIA articles! The Merchant Navy is the maritime register of the United Kingdom, and describes 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.