Anglo–German naval arms race in the context of Fleet in being

The dreadnought was the predominant type of battleship in the early 20th century. The first of the kind, the Royal Navy's HMS Dreadnought, had such an effect when launched in 1906 that similar battleships built after her were referred to as "dreadnoughts", and earlier battleships became known as pre-dreadnoughts. Her design had two revolutionary features: an "all-big-gun" armament scheme, with an unprecedented number of heavy-calibre guns, and steam turbine propulsion. As dreadnoughts became a crucial symbol of national power, the arrival of these new warships renewed the naval arms race between the United Kingdom and Germany. Dreadnought races sprang up around the world, including in South America, lasting up to the beginning of World War I. Successive designs increased rapidly in size and made use of improvements in armament, armour, and propulsion throughout the dreadnought era. Within five years, new battleships outclassed Dreadnought herself. These more powerful vessels were known as "super-dreadnoughts". Most of the original dreadnoughts were scrapped after the end of World War I under the terms of the Washington Naval Treaty, but many of the newer super-dreadnoughts continued serving throughout World War II.

Dreadnought-building consumed vast resources in the early 20th century, but there was only one battle between large dreadnought fleets. At the Battle of Jutland in 1916, the British and German navies clashed with no decisive result. The term dreadnought gradually dropped from use after World War I, especially after the Washington Naval Treaty, as virtually all remaining battleships shared dreadnought characteristics; it can also be used to describe battlecruisers, the other type of ship resulting from the dreadnought revolution.

HMS Dreadnought was a Royal Navy battleship, the design of which revolutionised naval power. The ship's entry into service in 1906 represented such an advance in naval technology that her name came to be associated with an entire generation of battleships, the dreadnoughts, as well as the class of ships named after her. Likewise, the generation of ships she made obsolete became known as pre-dreadnoughts. Admiral Sir John "Jacky" Fisher, First Sea Lord of the Board of Admiralty, is credited as the father of Dreadnought. Shortly after he assumed office in 1904, he ordered design studies for a battleship armed solely with 12 in (305 mm) guns and a speed of 21 knots (39 km/h; 24 mph). He convened a Committee on Designs to evaluate the alternative designs and to assist in the detailed design work.

Dreadnought was the first battleship of her era to have a uniform main battery, rather than having a few large guns complemented by a heavy secondary armament of smaller guns. She was also the first capital ship to be powered by steam turbines, making her the fastest battleship in the world at the time of her completion. Her launch helped spark a naval arms race as navies around the world, particularly the Imperial German Navy, rushed to match it in the build-up to the First World War.