Fully responsible government was granted to Canada in 1840, and gradually extended to the other colonies. In 1854 a separate secretary of state for the colonies was appointed at home, and the colonial office was established on its present footing. In India, as in the colonies, there came with the growing needs of empire a recognition of the true relations of the parts to each other and of the whole to the crown. In 1858, on the complete transference of the territories of the East India Company to the crown, the board of control was abolished, and the India Council, under the presidency of a secretary of state for India, was created. It was especially provided that the members of the council may not sit in parliament.

Thus, although it has not been found practicable in the working of the British constitution to carry out the full theory of the direct and exclusive dependence of colonial possessions on the crown, the theory is recognized as far as possible. It is understood that the principal sections of the empire enjoy equal rights under the crown, and that none is subordinate to another. The intervention of the imperial parliament in colonial affairs is only admitted theoretically in so far as the support of parliament is required by the constitutional advisers of the crown. To bring the practice of the empire into complete harmony with the theory it would be necessary to constitute, for the purpose of advising the crown on imperial affairs, a council in which all important parts of the empire should be represented.

The gradual recognition of the constitutional theory of the British empire, and the assumption by the principal Imperialism. colonies of full self-governing responsibilities, has cleared the way for a movement in favour of a further development which should bring the supreme headship of the empire more into accord with modern ideas.

It was during the period of domination of the "Manchester school," of which the most effective influence in public affairs was exerted for about thirty years, extending from 1845 to 1875, that the fullest development of colonial self-government was attained, the view being generally accepted at that time that self-governing institutions were to be regarded as the preliminary to inevitable separation. A general inclination to withdraw from the acceptance of imperial responsibilities throughout the world gave to foreign nations at the same time an opportunity by which they were not slow to profit, and contributed to the force of a reaction of which the part played by Great Britain in the scramble for Africa marked the culmination. Under the increasing pressure of foreign enterprise, the value of a federation of the empire for purposes of common interest began to be discussed. Imperial federation was openly spoken of in New Zealand as early as 1852. A similar suggestion was officially put forward by the general association of the Australian colonies in London in 1857. The Royal Colonial Institution, of which the motto "United Empire" illustrates its aims, was founded in 1868. First among leading British statesmen to repudiate the old interpretation of colonial self-government as a preliminary to separation, Lord Beaconsfield, in 1872, spoke of the constitutions accorded to the colonies as "part of a great policy of imperial consolidation." In 1875 W. E. Forster, afterwards a member of the Liberal government, made a speech in which he advocated imperial federation as a means by which it might become practicable to "replace dependence by association." The foundation of the Imperial Federation League - in 1884, with Forster for its first president, shortly to be succeeded by Lord Rosebery - marked a distinct step forward.

The Colonial Conferences of 1887 and subsequent years (the title being changed to Imperial Conference in 1907), in which colonial opinion was sought and accepted in respect of important questions of imperial organization and defence, and the enthusiastic loyalty displayed by the colonies towards the crown on the occasion of the jubilee manifestations of Queen Victoria's reign, were further indications of progress in the same direction. Coincidently with this development, the achievements of Sir George Goldie and Cecil Rhodes, who, the one in West Africa and the other in South Africa, added between them to the empire in a space of less than twenty years a dominion of greater extent than the whole of British India, followed by the action of a host of distinguished disciples in other parts of the world, effectually stemmed the movement initiated by Cobden and Bright. A tendency which had seemed temporarily to point towards a complacent dissolution of the empire was arrested, and the closing years of the 19th century were marked by a growing disposition to appreciate the value and importance of the unique position which the British empire has created for itself in the world.

No stronger demonstration of the reality of imperial union could be needed than that which was afforded by the support given to the imperial forces by the colonies and India in the South African War. It remained only to be seen by what process of evolution the further consolidation of the empire would find expression in the machinery of government. A step in this direction was taken in 1907, when at the Colonial Conference held in London that year it was decided to form a permanent secretariat to deal with the common interests of the self-governing colonies and the mother-country. It was further decided that conferences, to be called in future Imperial Conferences, between the home government and the governments of the self-governing dominions, should be held every four years, and that the prime minister of Great Britain should be ex officio president of the conference. No executive power was, however, conferred upon the conference.

The movement in favour of tariff reform initiated by Mr Chamberlain (q.v.) in 1903 with the double object of giving a preference to colonial goods and of protecting imperial trade by the imposition in certain cases of retaliative duties on foreign goods, was a natural evolution of the imperialist idea, and of the fact that by this time the trade-statistics of the United Kingdom had proved that trade with the colonies was forming an increasingly large proportion of the whole. In spite of the defeat of the Unionist party in England in 1906, and the accession to power of a Liberal government opposed to anything which appeared to be inconsistent with free trade, the movement for colonial preference, based on tariff reform, continued to make headway in the United Kingdom, and was definitely adopted by the Unionist party. And at the Imperial Conference of 1907 it was advocated by all the colonial premiers, who could point to the progress made in their own states towards giving a tariff preference to British goods and to those of one another.