Old cruisers were costly ASW substitutes

HMS Calypso was sunk by the Italian submarine Bagnolini while performing work far removed from a modern cruiser's ideal role. Using a total of 28 Royal Navy cruiser losses, World War I-era C-class ships account for roughly six. Their limited anti-submarine capability made them costly substitutes for purpose-built escorts. Replacing those losses therefore required deciding whether the mission needed a new cruiser at all, rather than automatically ordering another ship of the same type.