The first battlecruisers were designed in the United Kingdom, in the first decade of the century, as a development of the armoured cruiser, at the same time as the dreadnought succeeded the pre-dreadnought battleship.
The original aim of the battlecruiser was to hunt down slower, older armoured cruisers and destroy them with heavy gunfire.
There was also renewed interest in large "cruiser-killer" type warships, but few were ever begun, as construction of battleships and battlecruisers were curtailed in favor of more-needed convoy escorts, aircraft carriers, and cargo ships.
The list includes armed vessels that served during the war and in the immediate aftermath, inclusive of localized ongoing combat operations, garrison surrenders, post-surrender occupation, colony re-occupation, troop and prisoner repatriation, to the end of 1945.
Ships are designated to the country under which they operated for the longest period of the Second World War, regardless of where they were built or previous service history.