In 1828, the British declared martial law and in 1830 they unsuccessfully attempted to force hostile Aboriginal nations from the settled districts in a military operation called "the Black Line".

[10] Although commercial sealing on Van Diemen's Land had begun in late 1798, the first significant European presence on the island came in September 1803 with the establishment of a small British military outpost at Risdon Cove on the Derwent River near present-day Hobart.

[27] Clements states that the main reasons for frontier violence against Aboriginal people were revenge, killing for sport, sexual desire for women and children, and suppression of the native threat.

"[29] George Arthur, governor of the colony since May 1824, had issued a proclamation on his arrival that placed Aboriginal people under the protection of British law and threatened prosecution for anyone who murdered them.

The Colonial Times newspaper advocated the removal of all Aboriginal people from the settled districts to an island in the Bass Strait, warning: "if not, they will be hunted down like wild beasts, and destroyed!

"[30][31] On 29 November 1826, Arthur issued a notice authorising settlers to treat hostile Aboriginal groups as open enemies and to use arms to force them from the settled districts.

[47] In January 1828, he proposed settling the Aboriginal people "in some remote quarter of the island, which should be reserved strictly for them, and to supply them with food and clothing, and afford them protection ... on condition of their confining themselves peaceably to certain limits".

"[53] Arthur admitted that the British were "the first aggressors" but thought continued violence could only be prevented by enforcing the ban on Aboriginal people entering the settled areas.

[55][56] Violence escalated from August to October 1828, with the Oyster Bay, Big River, Ben Lomond and Northern peoples launching raids on stock huts during which 15 colonists were killed in 39 attacks.

[57][58] However, the proclamation also stated:... that the actual use of arms be in no case resorted to, if the Natives can by other means be induced or compelled to retire into the places and portions of this Island herein before excepted from the operation of Martial Law; that bloodshed be checked, as much as possible; that any Tribes which may surrender themselves up, shall be treated with every degree of humanity; and that defenceless women and children be invariably spared.

[61] About 500 Aboriginal people from five clan groups were still operating in the settled districts when martial law was declared and Arthur's first action was to encourage civilian parties to capture them.

[76] In its report, published in March 1830, the committee stated that the Aboriginal people had lost their sense of superiority of white men, no longer feared British guns, and were now on a systematic plan of attacking the colonists and their possessions.

"[79] Arthur accepted most of the committee's recommendations but only deployed a small number of additional mounted police due to the expense and a shortage of horses in the colony.

The Aborigines Committee and Executive Council also advised him that stronger measures were required to subdue the hostile Oyster Bay and Big River nations.

[84] He also ordered every able-bodied male colonist to assemble on 7 October at one of seven designated places to join a massive drive to sweep the hostile Aboriginal people from the settled districts in a military campaign which became known as the Black Line.

The conflict led to the Cape Grim massacre of 10 February 1828 in which shepherds armed with muskets ambushed up to 30 Aboriginal people as they collected shellfish at the foot of a cliff.

[96] Separated into three divisions and aided by Aboriginal guides, they formed a staggered front more than 300 km long that began pushing south and east across the Settled Districts from 7 October.

Although two of the divisions met in mid-October, the difficult terrain soon resulted in the cordon being broken, leaving many wide gaps through which the Aboriginal people were able to easily pass.

[103] In February 1831, the Aborigines Committee issued a report recommending that settlers should remain vigilant and that parties of armed men should be stationed in the most remote stock huts.

In response, up to 150 stock huts were turned into ambush locations, military posts were established on native migratory routes and new barracks were built at Spring Bay, Richmond and Break O'Day Plains.

[106] In February, Arthur appointed Robinson to head an Aboriginal Establishment on the Furneaux Islands and authorised him to negotiate the surrender of the remaining Big River and Oyster Bay people.

[107][108] In June, Robinson and a party of Aboriginal negotiators set off to locate a resistance group led by Umarrah which had conducted a series of raids killing several colonists.

[109] The public mood, however, swung further against Arthur's conciliatory approach after an Aboriginal group led by Montpelliatta conducted further raids in the Great Western Tiers culminating in the death of two prominent settlers in August.

[117][5] Arthur authorised Robinson to negotiate the surrender of the remaining southwestern and western Aboriginal clans and their removal to Flinders Island, believing that this would be the only way of saving them from extermination at the hands of settlers while providing them with the benefits of British civilisation and Christianity.

Lydall Ryan, citing studies by N.J.B Plomley, Rhys Jones, Colin Pardoe and Harry Lourandos, reaches a figure of 7,000 spread throughout the island's nine nations.

[153] However, other historians – including Henry Reynolds, Richard Broome, and Nicholas Clements – do not agree that the colonial authorities pursued a policy of destroying the Indigenous population, although they do acknowledge that some settlers supported extermination.

He concludes: "The colonial government from 1832 to 1838 ethnically cleansed the western half of Van Diemen's Land and then callously left the exiled people to their fate.

He says that Arthur was determined to defeat the Aboriginal people and take their land, but believes that there is little evidence that he had aims beyond that objective and wished to destroy the Tasmanian race.

He says that, unlike genocidal determinations by Nazis against Jews in World War II, Hutus against Tutsis in Rwanda and Ottomans against Armenians in present-day Turkey which were carried out for ideological reasons, Tasmanian settlers participated in violence largely out of revenge and self-preservation.

[162] Lawson, in a critique of Reynolds' stand, argues that genocide was the inevitable outcome of a set of British policies to colonise Van Diemen's Land.