For four centuries the British realm depended upon sea power to defend its interest and independence against a myriad of threats both military and economic. During this time the Royal Navy established itself as the “Sovereign of the Seas,” helping transform England, and later Great Britain, from an unassuming island nation perched on the edge of the European continent to the center of a global empire. Yet the advent of World War II presented Britain’s maritime services with their greatest challenge to date. At stake was the survival of the nation.

Source: The Longest Campaign: Britain’s Maritime Struggle in the Atlantic and Northwest Europe, 1939–1945 by Brian Walter | Goodreads