The idea of an internal colony, as far as I know, comes from [[black liberation]] groups in the 20th century. The ideas is basically that the [[United States]], through its process of [[slavery]], created a [[nation]] of black people within it, who are thus oppressed. These groups would see the [[national liberation]] of these people into their own nation state (sometimes called “New Afrika”).
Other examples of internal colonies could include Siberia in Russia.