Imperial Preference referring to the low tariffs between the UK and her colonies which was abandoned after World War 2. Did other colonial empires adopt similar policies?
Although I would like to hear more on this topic, I can say that the Empire of Japan did create the Greater East Asian Co-Prosperity Sphere between its colonial holdings in Southeast Asia that it utilized for preferential inter-imperial trade in its quest for mercantilist autarky before World War II.
Source: The American Age by Walter LaFeber