Foreign observers at Royal Navy exercises

Did foreign observers attend major interwar Royal Navy exercises, and did they learn from them?

Usually not by invitation, though the United States was sometimes shown British exercises in the 1920s as a deliberate deterrent signal.

Foreign observers were generally not invited into major Royal Navy exercises. Other navies could appear with their own ships, but they should expect to maneuver around a fleet conducting its own training. The United States was occasionally invited during the 1920s for a more purposeful demonstration. In that setting, showing British capability could be a form of naval diplomacy intended to make war between the two powers look unattractive.