[jboles]

I’m not sure how much it counts for, but the federation of Australia was barely 13 years old at that time. Furthermore it’s flag was also the Union Jack.

When WW2 rolled around, the point was moot, with offensive forces literally on the doorstep - Darwin was bombed, and there were submarines inside Sydney’s harbour.

[Naga]

The Canadian flag was also the Union Jack until 1965!

[arcticbull]

Canada had its own flag in addition to the Union Jack between 1868 and 1965. A fairly typical British colonial flag - similar to British Hong Kong [1, 2], Australia, New Zealand, Cape Colony, etc. - with the Union Jack in the canton (upper-left quadrant) against a red background with a coat of arms in the bottom-right varying based on who was part of Canada at any given time. [3]

[1] Illustration: https://en.wikipedia.org/wiki/Flag_of_Hong_Kong_(1959–1997)#...

[2] During Protests: https://en.wikipedia.org/wiki/Flag_of_Hong_Kong_(1959–1997)#...

[3] https://en.wikipedia.org/wiki/Flag_of_Canada#/media/File:Can...