In 1808 Jamison, Macarthur, Blaxcell and other disaffected colonists joined forces with the New South Wales Corps to arrest and expel Bligh from Government House in a military "coup d'état" that has now become known colloquially in Australia as the Rum Rebellion. Following the "coup", Jamison served as the Naval Officer (Collector of Customs and Excise) in the colony's temporary, rebel government. He was also given back his seat on the magistrates' bench. This enabled him to take part in the rebel committees which interrogated Bligh's supporters and combed through Bligh's private papers, looking for evidence against him that might justify their mutinous actions.