Former Prime Minister Stephen Harper has given up his seat as an MP, leaving Canadian politics after more than 20 years to focus on his businesses.The news comes 10 months after Mr Harper lost the election to Justin Trudeau and then resigned as Conservative leader.He said representing Calgary in Parliament had been an honour.He was first elected as a Reform MP in 1993 and later led the Conservative Party to three election victories.In a written statement, he said: “Friends, we did a lot together, but I know the best is yet to come.”Our country must continue to serve as a model of prosperity and freedom.”Three election wins, no shortage of controversyFive things Stephen Harper got wrong He listed his achievements as cutting taxes and balancing the national budget. “We got tough on crime and put families first. We managed our G7 economy through the worst global recession …