can you mention any political achievement of his?
Called for Rhodesia to abolish black representation in parliament and adopt "a form of political apartheid".
William Harper (Rhodesian politician)
he called for Rhodesia to abolish black representation in parliament and adopt "a form of political apartheid". 
who was william harper? He was a politician, general contractor and Royal Air Force fighter pilot where was he born? Born in Calcutta which political party was he a member of? Dominion Party
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William Harper (Rhodesian politician) [SEP] Introduction
He subsequently became a vocal critic of the Prime Minister, greeting each step Smith made towards settlement with black nationalists during the Bush War with public indignation. By the time black majority rule began in Zimbabwe Rhodesia in 1979, following the Internal Settlement of the previous year, Harper had left for South Africa, being unwilling to accept majority rule in Rhodesia. He died in 2006 at the age of 90.