Well the British Empire was certainly one of THE worst and most evil happenings on planet Earth, the slaughter and the cause of death of millions, scorched Earth policies, massacre of Red Indians, Zulu's....probably the worlds first ever concentration camps in South Africa where thousands of children starved to death, Aborigines hunted like animals. In fact everywhere Britain invaded the people were treated like animals, 2nd class citizens.
In the 1870s while under British rule, India was swept with several famines which led to the deaths of over five million of its people. Simultaneously with these deaths from starvation, malnutrition, and disease India’s exports of grain to the rest of the world, ordered and supervised by officials of the British Empire, increased, in some cases to record levels.
Under British rule, India provided food to the rest of the world as its own people starved and died.
One of the common themes throughout the life of the British Empire was its proclivity for taking portions of the civilian population, arming and training them as an Army, and using them to control the remaining civilian population
Here's a small list of atrocities committed by the British.
10 Atrocities Committed by the British Empire that They Would Like to Erase from History Books (historycollection.com)
I'm glad you brought up Australia To those that are aware of British mass murder as ordered by British Governments, the scale of cataloguing these crimes becomes a task in itself. The invasion and decimation of Aboriginal Australia was and is entirely a British affair. When Britain devastates a 65,000 year old culture and carries out unthinkable crimes to take over land and exterminate the indigenous population how do we term Britain other than a mass murderer?
The Aboriginal experience is depressingly similar to that of Native Americans in the United States. British settlers viciously drove the Aborigines from their land, massacring thousands with impunity.
Colonial settlers simply shot all blacks on sight (sometimes for a shilling reward from the local Gomnt.) and took the children to work as unpaid labor. Mechanisms used by the British were shooting, food poisoning (distributing poisoned flour – premeditated murder) burning, biological warfare using variola, disease, rape and ethnocide as well as cultural destruction.
The British took over a quarter of the world by brute force and racist murdering. Yet statues of people of the ilk of Cecil Rhodes still stand.
As for me living here, I would gladly leave or not come here in the first place if it meant one Aboriginal life could have been saved.