China, the country was never a colony under British rule - perhaps you're thinking of the island leased to Britain, Hong Kong.

China did have interactions with Britain, disputes over trade, access, addictive drug running, gunboat diplomacy et al. but these usually fall under British Imperialism rather than British Colonialism.

I think that's the previous posters point. The OP argued that countries were better off in the long run with British colonialism than without. I think China vs India is the counter example.