The India Office was the British government department responsible for the direct administration of India during the British Raj. It was headed by the Secretary of State for India, who was a member of the British Prime Minister's Cabinet.
The India Office was intimately involved in the formation of Indian and Imperial policy throughout its existence. It worked behind the scenes, forming the nexus between the British political, bureaucratic and commercial reality and the Government of India.
The Office was described thus by Lord George Hamilton -
The Viceroy of India was the head of the British administration in India. However, he reported directly to the Secretary of State for India, a British government minister, and through him to the Cabinet.
One major institutional reform - the British Government's takeover of the responsibilities of the East India Company (1858) - and three technical advances - the opening of the London-India telegraph (1865), the opening of the Suez Canal (1869) and the related replacement of sailing ships by faster steam vessels - allowed the British Government, through the Secretary of State for India, to effectively control the Viceroy. In turn, the spread of the Indian railway and telegraph system allowed the Viceroy and his secretariat to fully subordinate the Government of India machine. During this process, the India Office provided the bureaucratic and policy ammunition that the Secretaries of State of the late 19th century used to convert the Viceroy and Government of India into little more than the agents of the Government of the United Kingdom.
During the period 1910–1947, successive political reforms led to ever greater decentralization of power within India and the devolution of increased authority to both British Indian officials and Indian politicians. The India Office was intimately involved in this process, at times resisting these changes.
The India Office proper existed until 1947, when India was granted independence and the state of Pakistan was created.
In spite of its manifest importance in understanding the history of pre-1947 India, no analytical investigation of the structure and function of the India Office exists for the period beyond 1924.
After Indian partition and independence in 1947, the India Office was converted into the Burma Office, which oversaw Burma until the colony's own independence the next year. The department was then abolished completely.