It was Admiral John Fisher, the First Sea Lord, that was the driving-force behind the development of the Dreadnought that was built at Portsmouth Dockyard between October 1905 and December 1906. The Dreadnought was the most heavily-armed ship in history. She had ten 12-inch guns (305 mm), whereas the previous record was four 12-inch guns. The gun turrets were situated higher than user and so facilitated more accurate long-distance fire. In addition to her 12-inch guns, the Dreadnought also had twenty-four 3-inch guns (76 mm) and five torpedo tubes below water. In the waterline section of her hull, the Dreadnought was armoured by plates 28 cm thick.

The Dreadnought was the first major warship driven solely by steam turbines. The four sets of Parsons steam turbines with a total output of 24,700 h.p. were used. The Dreadnought was also faster than any other warship and could reach speeds of 21 knots. A total of 526 feet long (160.1 metres) the Dreadnought had a crew of over 800 men.

The design of the Dreadnought was so revolutionary that all similar warships were also called Dreadnoughts. The introduction of this new warship resulted in an arms race between Britain and Germany. By 1914 the British Navy had nineteen Dreadnoughts (thirteen under construction), compared with Germany's thirteen (seven under construction). Other fleets with Dreadnoughts at sea by 1914 were: United States (8), France (8), Japan (4), Austria-Hungary (2) and Italy (1).

In 1915 Britain produced the Queen Elizabeth, the first of the Super-Dreadnoughts. This warship had eight 15-inch guns, each capable of firing a 1,920-pound projectile 35,000 yards. This was followed by four other ships of this design: Warspite, Barham, Valiant and Malaya. All five ships survived the First World War, and heavily modified, served in the Second World War.