Barton had only been commissioned to form a government one week before he became prime minister, due to what became known as the "Hopetoun Blunder". The new governor-general Lord Hopetoun arrived in Australia on 15 December 1900. He was tasked by the Colonial Office with selecting someone to form a caretaker government prior to the first federal election; this individual would be Australia's first prime minister. It was widely assumed that Barton would be offered the position, and he had begun making preparations for the role, including a draft platform for the first federal elections. On 19 December, however, Hopetoun commissioned William Lyne to form a government. His reasons for doing so have been debated, but his decision was widely regarded as a mistake. Lyne, the premier of New South Wales, had actively campaigned against federation, and the leading politicians in each of the other colonies refused to serve under him. On 24 December, he informed Hopetoun that he was unable to form a government and advised him to send for Barton. As a result, the composition of Australia's first cabinet was not formally announced until 30 December, two days before it was sworn in.