In July 1801, Governor King overturned a sentence of one year’s imprisonment for Lieutenant James Marshall of the Earl Cornwallis, who had been convicted of assaulting Macarthur and Captain Abbott during their investigation into a theft. King referred the matter for trial in England on the grounds that the court had refused to hear Marshall’s objection to an officer of the NSW Corps hearing the case. Macarthur saw this as a slight, and tried to organise a petty social boycott of Governor King and when his superior, Colonel Paterson, refused to co-operate Macarthur used personal material to try and blackmail him. This resulted in Paterson challenging Macarthur to a duel in which Paterson was severely wounded in the shoulder. Governor King had Macarthur arrested then released him and appointed him as commandant on Norfolk Island to try and defuse things. Macarthur refused to comply and demanded a court martial by his fellow officers. King, realising that this would be pointless, sending Macarthur to England for trial. Macarthur sailed on the Hunter, departing Sydney in November 1801. On this same vessel, Governor Hunter had sent a ‘very bulky’ dispatch, denouncing Macarthur. This dispatch went missing, apparently during the voyage. According to Evatt, in Rum Rebellion, Macarthur had a powerful motive for stealing and destroying it. Evatt infers that Macarthur, ‘or some close associate’, was responsible.
One year later, when Macarthur reached England, the courts ruled that the matter should be tried in Sydney, where all the evidence and witnesses were. The Duke of York, Commander-in-Chief hello of the British Army, rebuked King for failing to deal with the matter himself, but confirmed that King’s orders releasing Macarthur and transferring him to Norfolk Island stood. To avoid the posting, Macarthur resigned his commission, eventually returning to Sydney in 1805 after an absence of nearly four years to run his businesses as a private citizen. Governor King had declared while Macarthur was in London that, “if Captain Macarthur returns here in any official character, it should be that of Governor, as one-half the colony already belongs to him, and it will not be long before he gets the other half.”
*All biographical details are taken from Wikipedia for education purposes only.