The britain coming out of world war 2 was very different from the britain entering WW1, in a way the late-comer nations refusing to be starved by the empires by going hyper-imperialist destroyed the age of empires.
For clarity I'm talking proper empire where you send in troops and install a viceroy, not just trading with places which is mostly what China does. The Taiwan thing is a special case of the communist party trying to take the remaining bit of China which has held out for a century.