Who gained most from the interwar naval treaty system?

Which country truly won the interwar naval treaty system?

Italy, because the treaties elevated it to parity with France, constrained its rivals, and protected it from Britain's overwhelming superiority without requiring Italy to match their naval investment.

The treaty system constrained the fleets and building choices of Britain and the United States despite helping them retire unwanted ships. Italy gained status alongside France, constrained its principal Mediterranean rival, and reduced the ability of the stronger Royal Navy to overwhelm it. The 1930 London system did not bind Italy or France to the same submarine limitations, extending Italy's room for manoeuvre. Italy's limited infrastructure and Mussolini's policy prevented it from exploiting every advantage, but the diplomatic and legal position it received cost comparatively little.