The history of colonialism normally focusses on the socio-economic losses of colonies, and the benefits of metropoles are a much less-studied field. Our study indicates that the flow of resources, rent and personal wealth should not be downplayed as factors of economic growth in the key Empires, although information on most subjects is limited. This importance could be demonstrated (although not fully quantitatively evaluated) by India–United Kingdom relations before 1913. We highlight the key channels of this influence (trade, investment and migration), and the persistence of the income gaps between the dominant and dependent countries until their independence.