Clarkson describes one of her earliest memories as that of hiding in several Hong Kong basements during the Japanese invasion of the territory in 1941. It was only through his Canadian government connections that her father gained his family the opportunity in 1942 to flee the occupation to Canada, as part of the repatriating of Canadian government staff from the fallen city. Even so, the Chinese Immigration Act, 1923, prevented the Poys' immediate entry into the country until the Department of External Affairs intervened and cited an unfilled quota in the prisoner of war exchange programme with the Japanese Imperial Forces that would permit the Poy family free passage into Canada. The family settled in Ottawa, though William had lost almost all of his substantial fortune, and the Poys lived in a cramped duplex. Clarkson attended public school in the city and, in October 1951, was lined up with her class to see Princess Elizabeth, Duchess of Edinburgh (later Queen Elizabeth II), as the royal motorcade passed through the city.