 During the early 1870s South Australia 's defence was solely dependent on the volunteer military , and a few artillery pieces purchased during earlier war <unk> . British troops had been withdrawn from the Australian colonies in 1870 , leaving the state dependent on its own military resources . In a report to the government in 1866 , Colonel <unk> and Major Peter Scratchley recommended establishment of a permanent military force . In 1876 the South Australian government , along with those from New South Wales , Victoria and Queensland requested from the War Office that Major General Sir William Jervois , a noted coastal fortification expert , be appointed to advise on defence needs . He arrived in Sydney in mid @-@ 1877 with then Lieutenant Colonel Scratchley . The 1877 report , delivered after he became South Australian Governor , called for three batteries , at Largs Bay , Semaphore and Glenelg , connected by a military road and supported by field gun emplacements , naval elements and mobile forces . He determined that South Australia 's most probable defence risk was an attack by up to two ships rather than a larger force , and this formed the basis of the final fortification design . His report called for Military Road to be extended to Marino , an electro @-@ contact torpedo station be established on Torrens Island and that a gun boat be provided . In November 1878 the government passed the Military Forces Act , which provided for the raising of a permanent military force and reserve . Two volunteer reserve rifle companies were formed in 1878 and a permanent artillery unit in 1882 . 
