This is a list of ironclads of the Royal Navy of the United Kingdom. An ironclad was a steam-propelled warship in the early part of the second half of the 19th century, protected by iron or steel armour plates.
The term battleship was not used by the Admiralty until the early 1880s[citation needed], with the construction of the Colossus class. Prior to this point, a wide range of descriptions were used.
While the introduction of the ironclad is clear-cut, the boundary between 'ironclad' and the later 'pre-dreadnought battleship' is less obvious, as the characteristics of the pre-dreadnought evolved. For the sake of this article, the Royal Sovereign-class are treated as the first pre-dreadnoughts on account of their high freeboard and mixed battery of guns.