, flagship of the Second Sea Lord of the Royal Navy]]A flagship is the ship used by the commanding officer of a group of naval ships. The term originates from the custom of the commanding officer (usually, but not always, a flag officer) to fly a distinguishing flag. Used in this way, "flagship" is fundamentally a temporary designation; the flagship is wherever the admiral is flying his flag. However, admirals have always needed additional facilities; a meeting room large enough to hold all the captains of the fleet, and a place for the admiral's staff to make plans and draw up orders. In the age of sailing ships, the flagship was typically a first-rate; the aft of one of the three decks would become the admiral's quarters and staff offices. This can be seen today on HMS Victory, the flagship of Admiral Nelson at the Battle of Trafalgar, now at Portsmouth, England. In the 20th century, ships became large enough that most types