The Union Jack in the corner of the flag has traditionally been the flag of a British colony. In fact, the United Kingdom still has 14 British Overseas Territories, all but one of which use the Union Jack on their flag:
Anguilla |
Bermuda |
British Antarctic Territory |
British Indian Ocean Territory |
British Virgin Islands |
Cayman Islands |
Falkland Islands |
Gibraltar 1875-1982 |
Gibraltar |
Montserrat |
Pitcairn |
St. Helena and Dependencies |
South Georgia and South Sandwich Islands |
British Sovereign Base Areas in Cyprus |
Turks and Caicos Islands |
And many former British colonies used the Union Jack. Below is a table, by no means exhaustive.
Aden |
Antigua and Barbuda |
Australia |
Bahamas |
Barbados |
British Central Africa |
British Guyana |
British Honduras |
Canada |
Cyprus |
East Africa |
Fiji |
Grenada |
Lagos |
Mauritius |
New Zealand |
Niger Coast |
Nigeria |
Southern Nigeria |
North Borneo |
Nyasaland |
Rhodesia and Nyasaland |
Seychelles |
Solomon Islands |
Somaliland |
Tuvalu |
Do you notice a pattern here?
Now, how many of these independent former colonies still use the Union Jack?
Four:
Australia |
Fiji |
New Zealand |
Tuvalu |
Kind of embarassing really.
Why do Fiji, New Zealand and Tuvalu keep the Union Jack on their flag? I don't know, that's their business.
What is clear, however, is that the Union Jack - in particular the "Blue Ensign" theme - is the mark of a British colony. As such, it is inappropriate for the flag of a fully independent country like Australia.