Between 23 Aug 1849 and 4 Mar 1880, 28 of my direct ancestors (10 x 3rd great grandparents, 16 x 2nd great grandparents and 2 x great grandparents) emigrated from England, Scotland and Wales to South Australia (mostly), Western Australia and Victoria.
I have always understood these ancestors to be British by nationality, and I had assumed that the subset of their descendants who were also my direct ancestors could be considered Australian, because they were all born in South Australia, but that the earlier ones would not have had Australian citizenship because Australia consisted of separate colonies until federation.
I imagined that on 26 Jan 1901 when Australia became federated, that any of my direct ancestors living at the time in Australia, probably became Australian citizens overnight.
However, thanks to the National Archives of Australia I now know:
At Federation in 1901, ‘British subject’ was the sole civic status noted in the Australian Constitution. The Australasian Federal Convention of 1897–98 was unable to agree on a definition of the term ‘citizen’ and wanted to preserve British nationality in Australia. An administrative concept of citizenship arose from the need to distinguish between British subjects who were permanent residents and those who were merely visitors. This was necessary for the Commonwealth to exercise its powers over immigration and deportation. Motivated by the nationalism of Arthur Calwell, the Minister for Immigration 1945–49, this administrative concept was formalised in the Nationality and Citizenship Act 1948. In 1958 the Act was amended so that naturalisation could only be revoked if obtained by fraud. This prevented a naturalised person being stripped of citizenship and deported.
Throughout the 1960s, Australian citizens were still required to declare their nationality as British. The term ‘Australian nationality’ had no official recognition or meaning until the Act was amended in 1969 and renamed the Citizenship Act. This followed a growing sense of Australian nationalism and the declining importance for Australians of the British Empire. In 1973 the Act was renamed the Australian Citizenship Act. It was not until 1984 that Australian citizens ceased to be British subjects.
Furthermore, thanks to @bgwiehle pointing me at the Wikipedia article "Australian nationality law" I now know that:
A separate Australian citizenship came into existence on 26 January 1949. Persons who had been British subjects on that date acquired the new Australian citizenship if ... born or naturalised in Australia (in general, birth in Australia automatically conferred British subject status)
My last great grandparents died in 1948, which now makes it easy for me to know that of my direct ancestors it was only my grandparents and parents who were alive to become Australian citizens in 1949.
With all my grandparents passing away between 1961 and 1982, I now know that they remained British subjects throughout their lifetimes but died as Australian citizens.
If anyone is knowledgeable in this area, I am keen to know whether my parents' passports (or records of those applications, which happened after 1984), are the only formal documentation that confirmed their Australian nationality/citizenship?
There are no new details about their lives that I would expect to learn from such documentation so this question is really just designed to help me to understand how/when I and my direct ancestors became Australian and ceased to be British.