The United Kingdom Royal Navy plans to build one of the most advanced destroyer ships in the world. The Royal Navy (RN) is the United Kingdom's principal naval warfare force. Tracing its origins to the 16th century, it is the oldest service and is known as the Senior Service. From the end of the 17th century until well into the 20th century it was the most powerful navy in the world, playing a key part in establishing the British Empire as the dominant world power. Due to this historical prominence, it is usual – even among non-Britons – to refer to it as "The Royal Navy" without qualification.
Following victory in the First World War, the Royal Navy was significantly reduced in size, although at the onset of the Second World War it was still the largest in the world. By the end of the Second World War, the United States Navy had emerged as the world's largest. During the course of the Cold War, the Royal Navy transformed into a primarily anti-submarine force, hunting for Soviet submarines, mostly active in the GIUK gap. Following the collapse of the Soviet Union, its focus has returned to expeditionary operations around the world.
The navy maintains a fleet of technologically sophisticated ships including a landing platform helicopter, two amphibious transport docks, four ballistic missile submarines (which maintain the UK's nuclear deterrent), seven nuclear fleet submarines, six guided missile destroyers, 13 frigates, 15 mine-countermeasure vessels and 22 patrol vessels. As of 1 August 2015, there are 76 commissioned ships (including submarines) in the Royal Navy, plus 12 commissioned ships of the Royal Fleet Auxiliary (RFA); there are also four Merchant Navy ships available to the RFA under a private finance initiative. The RFA replenishes Royal Navy warships at sea, and augments the Royal Navy's amphibious warfare capabilities through its three Bay-class landing ship vessels. The total displacement of the Royal Navy is approximately 337,000 tonnes (603,000 tonnes including the Royal Fleet Auxiliary and Royal Marines).
The Royal Navy is part of Her Majesty's Naval Service, which also includes the Royal Marines. The professional head of the Naval Service is the First Sea Lord, an admiral and member of the Defence Council of the United Kingdom. The Defence Council delegates management of the Naval Service to the Admiralty Board, chaired by the Secretary of State for Defence. The Royal Navy currently operates three bases in the United Kingdom where commissioned ships are based; Portsmouth, Clyde and Devonport, Plymouth, the last being the largest operational naval base in Western Europe.
Main articles: History of the Royal Navy and Royal Scots Navy
Development of an English navy
The strength of the fleets of the Kingdom of England was an important element in the kingdom's power in the 10th century. At one point Aethelred II had an especially large fleet built by a national levy of one ship for every 310 hides of land, but it is uncertain whether this was a standard or exceptional model for raising fleets. During the period of Danish rule in the 11th century, the authorities maintained a standing fleet by taxation, and this continued for a time under the restored English regime of Edward the Confessor (reigned 1042–1066), who frequently commanded fleets in person.
The Battle of Sluys as depicted in Froissart's Chronicles; late 14th century
English naval power seemingly declined as a result of the Norman conquest. Medieval fleets, in England as elsewhere, were almost entirely composed of merchant ships enlisted into naval service in time of war. From time to time a few "king's ships" owned by the monarch were built for specifically warlike purposes; but, unlike some European states, England did not maintain a small permanent core of warships in peacetime. England's naval organisation was haphazard and the mobilisation of fleets when war broke out was slow.
With the Viking era at an end, and conflict with France largely confined to the French lands of the English monarchy, England faced little threat from the sea during the 12th and 13th centuries, but in the 14th century the outbreak of the Hundred Years War dramatically increased the French menace. Early in the war French plans for an invasion of England failed when Edward III of England destroyed the French fleet in the Battle of Sluys in 1340. Major fighting was thereafter confined to French soil and England's naval capabilities sufficed to transport armies and supplies safely to their continental destinations. However, while subsequent French invasion schemes came to nothing, England's naval forces could not prevent frequent raids on the south-coast ports by the French and their Genoese and Castilian allies. Such raids halted finally only with the occupation of northern France by Henry V.