The Royal Navy

The Royal Navy of the United Kingdom is the oldest of the British armed services (and is therefore known as the Senior Service). From the mid-18th 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 from 1815 until the early 1940s. In World War II, the Royal Navy operated almost 900 ships. During the Cold War, it was transformed into a primarily anti-submarine force, hunting for Soviet submarines, mostly active in the GIUK gap. With the collapse of the Soviet Union, its role for the 21st century has returned to focus on global expeditionary operations.

The Royal Navy is the second-largest navy of the NATO alliance, in terms of the combined displacement, approx. 400,000 tonnes (900,000 tonnes including RFA ships) of its fleet, after the United States Navy. There are currently 88 commissioned ships in the Royal Navy (110 with RFA ships), including aircraft carriers, a helicopter carrier, landing platform docks, ballistic missile submarines, nuclear fleet submarines, guided missile destroyers, frigates, mine counter-measures and patrol vessels. There are also the support of 22 vessels of the Royal Fleet Auxiliary. The Royal Navy's ability to project power globally is considered second only to the U.S. Navy. The Royal Navy maintains the United Kingdom's nuclear weapons.

The Royal Navy is a constituent component of the Naval Service, which also comprises the Royal Marines, Royal Fleet Auxiliary, Royal Naval Reserve and Royal Marines Reserve. The Royal Navy numbers 37,500 people of whom approximately 6,000 are in the Royal Marines.