Italy builds a sixteen-gun super-battleship

How plausible was an Italian super-battleship with sixteen 16-inch guns, and how would Britain and France respond?

It was a distant concept requiring a huge industrial expansion, and its long lead time would let Britain and France answer with their own large-gun programs.

Sixteen 16-inch guns in four quadruple mountings imply a ship of roughly 65,000 tons once armor, machinery, and the beam needed for the turrets are included. A wide hull would also need greater length to reach the speed expected of a successor to the Littorio class. Italy would have to enlarge its shipbuilding infrastructure, giving Britain and France substantial warning. This was a distant concept beyond the immediate Littorio successor, so the response would depend on how rival battleship designs had developed by then. British ships with twelve 16-inch guns might already be in service. Several countries had the industrial capacity to develop very large naval guns, even if their results would differ in quality.