What is the main idea of "The Occasion for Speaking" by George Lamming?

The main idea in Lamming's, The Occasion for Speaking, is centered around explaining the idea of England.... the inferred superiority of its people, which has been passed down from generation to generation and which has through colonization destroyed the natives from the places it has colonized. It also speaks to the way that those people banded together through the end of colonization and forged a new country in reattaining their freedom.