Background: This feels like sort of a silly question for me to be asking after reading about the Victorian Age and the British Empire for several months, but here goes.
As I've read about the British Empire, a pretty clear tend has emerged; when the British open China to the opium trade, export food out of Ireland during a famine, squelch Indian weavers beneath the weight of British manufacturing, or otherwise exert economic influence and naval muscle abroad, they usually justify their actions, at least in part, as being in the interests of free trade. The same when they repeal the Corn Laws, or otherwise act more beneficently.
I understood Free Trade to mean the idea that trade between nations should not taxed or restricted, and that in the long run free markets operate to the benefit of all. But at the same time, I've read that the British empire was in many ways a closed system, one that restricted and taxed the trade of the colonies, both to weigh the benefits of trade in favor of the mother country, and to prevent them from trading with other European powers.
I don't expect any society to be free of contradiction, but this seems like a big one, and I'd like to understand it better. Was there a more of contest between Free Trade and mercantilism after 1800 then I'd believed? Or does the British regulation of her various overseas possessions represent more of a pragmatic, ad hoc, system of compromise to financial problems? Or have I just completely missed something really basic?
Question: What did the politicians and industrialists of the British Empire, after 1800, mean when they spoke about Free Trade? Especially in reference to the British colonies?