Gallagher and Robinson argue that imperialism is not just about colonies. Britain often controlled other regions without formally ruling them, using trade, finance, diplomacy, and military pressure. This is called an informal empire.
Free trade did not replace empire — it became a tool of empire.
Their key insight:
Britain preferred informal control when possible, and formal rule only when informal methods failed.
Gallagher and Robinson show that British imperialism was about controlling economies, not just territories, using free trade as a flexible tool of power.