Treaties, aviation assistance, and battlecruiser visits shaped Far Eastern signalling

The Sempill Mission coincided with the Royal Navy's 1921 higher-command conference, and the Air Ministry publicly claimed indifference while unofficially supporting the mission. The Nine-Power agreement promised respect for Chinese sovereignty, territorial integrity, and equal commercial opportunity among states that already possessed interests in China. HMS Renown's tour demonstrated that British capital ships could reach Japan, while later voyages by HMS Hood and HMS Repulse through Australia and Hawaii extended that visible presence across the Pacific. The Washington Naval Treaty then froze new bases, fortifications, and expanded coastal defences across much of the Pacific in an effort to reassure Japan and contain an expensive building race. Those restrictions made Singapore more important because it remained outside the prohibited area and could still be developed. The 1924 causeway to the Malay Peninsula nevertheless arrived before the naval base and its defences, exposing the gap between declaring a strategic hub and making it secure. Technical cooperation, diplomacy, fleet visits, and base policy all contributed to interwar naval signalling.