List of Canadian ministries
By convention, each Canadian ministry is formed when the chairing prime minister is appointed and dissolved when s/he leaves office. The one exception occurred during the premiership of Robert Borden whose wartime Unionist government is considered a separate ministry from the one he chaired as head of a Conservative government. Elections do not cause dissolution of the ministry unless they result in the government's defeat – this is in contrast to other Commonwealth realms such as Australia and the United Kingdom where a "new" ministry is considered to have been formed after every election regardless of the winner. Therefore, the twenty-eight ministries that have served Canada represent twenty-six occasions since Canadian Confederation that the premiership has changed hands and one occasion when a coalition government was formed by the sitting prime minister.