This question implies that there is a direct link between being a British colony and becoming a rich independent country, something I very much doubt. People tend to look at America, Australia, New Zealand and Hong Kong and say "Look at all these British colonies that are so well off today". Then they ask questions like this or "Why were British colonies more successful". The problem is of course that the data is cherry picked. Plenty of British colonies did not become rich. British Guiana, Sierra Leone, the Gold Coast, North and South Rhodesia, British Somaliland, Sudan, Burma, Papua New Guinea etc etc are all examples of British colonies that did not become particularly wealthy independent nations.