The 1921 Cairo Conference represented a major turning point in the reconfiguration of British regional policy in West Asia following the First World War. The emergence of a new regional order in West Asia after the war marked the beginning of a series of transformations that also affected Iran’s geopolitical position within its surrounding environment. Britain’s decisions, aimed at reformulating its regional policy and aligning it with a broader strategy for managing the emerging regional order at lower imperial costs, played a significant role in reshaping the political and security structures of West Asia. This article analyzes the process of power engineering undertaken by Britain within Iran’s geopolitical environment and seeks to explain the logic of indirect rule that has shaped the region over the past century. The primary objective of this study is to examine how the decisions and policy orientations consolidated during this period, within the framework of Britain’s broader strategy in West Asia, contributed to redefining Iran’s geopolitical position. The study employs an analytical approach based on archival sources. The findings indicate that, during this period, Britain, seeking to reduce the costs of imperial governance while consolidating its influence, pursued a transition from direct to indirect rule, the establishment of politically aligned entities, and reliance on air power as an instrument of control and power projection. These developments not only contributed to the creation of new political structures in the region but also transformed the security balances surrounding Iran and reconfigured Iran’s geopolitical position within Britain’s regional strategy.