The Colonial Office was a government department of the Kingdom of Great Britain and later of the United Kingdom, first created to deal with the colonial affairs of British North America but needed also to oversee the increasing number of colonies of the British Empire.
It was headed by the Secretary of State for the Colonies, known as the Colonial Secretary.
Prior to 1768, responsibility for the affairs of the British colonies was part of the duties of the Secretary of State for the Southern Department and a committee of the Privy Council known as the Board of Trade and Plantations.
In 1768 the separate American or Colonial Department was established, in order to deal with colonial affairs in British North America. With the loss of the American colonies, however, the department was abolished in 1782. Responsibility for the remaining colonies was given to the Home Office, and subsequently (1801) transferred to the War Office.
The War Office was renamed the War and Colonial Office in 1801, under a new Secretary of State for War and the Colonies, to reflect the increasing importance of the colonies. In 1825 a new post of Permanent Under-Secretary of State for the Colonies was created within this office. It was held by Robert William Hay initially. His successors were James Stephen, Herman Merivale, Frederic Rogers, Robert Herbert and Robert Henry Meade.