 The removal of all remaining garrison troops from Australian colonies excepting those retained and paid for by colonial governments as a result of the Cardwell reforms in the late 1860s forced a rethink of local defence preparedness, especially with the outbreak of hostilities between Russia and Britain in 1876.As a result, the Australian colonies requested the services of an Imperial Engineer to advise them on defence matters.Military engineers Scratchley and Jervois were sent.