Premise: The British Nationality Act (1981) had in effect prevented Hong Kong citizens from acquiring British citizenship, and thousands of people, anxious about their future under China's rule, were prompted to apply for citizenship elsewhere, notably in Canada and Australia.
Hypothesis: The British Nationality Act prompted people in Hong Kong who were unable to apply for British citizenship to apply to other countries like Canada and Australia where they could try to gain citizenship in order to leave an uncertain future in China. 
Label: entailment