HMS Clement was a British nuclear submarine in service with the Royal Navy in the 21st century.
The chief engineer of the Clement was the great-uncle of Malcolm Reed. When on routine patrol the vessel hit a mine left over from one Earth's world wars. Being trapped under an ice shelf the chief engineer sealed himself in the engine room in order to keep the reactor online so his comrades could abandon the ship in its escape pods.(ENT: "Minefield")
The USS Clement may have been named after this vessel.
The ship was referred to by Reed as the HMS Clement, even though the correct way to refer to ships with this prefix would be without the definite article ("the") as it is simply grammatically incorrect to say "the Her Majesty's Ship Clement".