When the Union of South Africa was formed in 1910, the electoral qualifications in use in each pre-existing colony were kept in place.

The first challenge to the Cape Qualified Franchise came with the Women's Enfranchisement Act, 1930 and the Franchise Laws Amendment Act, 1931, which extended the vote to women and removed property qualifications for the white population only – non-white voters remained subject to the earlier restrictions.

In 1936, the Representation of Natives Act removed all black voters from the common electoral roll and introduced three "Native Representative Members", white MPs elected by the black voters of the province and meant to represent their interests in particular.

[2] In its original form, its eastern boundary was Adderley Street, but with the abolition of Cape Town Castle in 1958 and Salt River in 1974, it came to extend across the width of the City Bowl in addition to Green Point itself.

Piet van der Byl, former cabinet minister, represented the seat from 1948 to 1966, and was widely respected on all sides of politics, as evidenced by the fact that he never faced opposition for re-election.