After 50s, the immigrants from mainland contributed the major growth of HK population. The HK government didn't treat these people differently. At the time, majority were under educated, and they were so use to social injustice, and comparing HK to the war tore mainland. HK was the best place ever. 60s were about the same, but the local elites became more visible, and the policy of the HK government was to protect the interest of the local elites. By the local elites, I mean those Chinese educated in the western world, or the two universities in HK, and those investors from Shanghai. The two groups that the HK government tried to suppress were the KMT leaning mainland immigrants usually had ties to the KMT militarise, and later became the back bone of the HK triads. The other group were the left leaning HK natives associated the Chinese communists. At this point, the living standard in HK wasn't that different from mainland, at least for the majority poor people, and the discrimination were basically the mistrust between Cantonese and people from other provinces. In the 70s, the different of living standard between HK and mainland became significant, and more immigrants from mainland came to HK. At this time, the native born had access to English education gained more opportunities and had a significant advantage over those new immigrants from China. Even though HK government did not discriminate, but the best jobs, the HK civil servants, required good English standing as any other professional good paying jobs. That became the major barrier to the new immigrants especially those who received their high education in mainland, and practically lost all their credentials. Late 70s, the discrimination against mainland Chinese became mainstream, and last for very long, perhaps, even till today.