In 1804 there were 572 fighting ships in the Royal Navy. The UK was engaged in a series of wars at the time which encouraged government to keep the force strong. In 1939 as war broke out the UK navy had 332 naval vessels. During the war there was a large expansion in the fleet, with 553 new ships added both to replace lost ships and to expand the size of the force. 58 new aircraft carriers were produced during the war years, for example.
Today in a period of relative peace there are just 67 fighting ships in the navy, including 18 small patrol boats with guns.