During the years from 1917 to 1926, Great Britain's relations with the overseas British dominions were profoundly and extensively modified, to a degree that made this decade a transitional period of the greatest importance in the history of the British empire–commonwealth. It marks the time when the dominions moved from a status of colonial autonomy under Britain's imperial aegis to a position where they could claim the right to practical independence in their international as well as domestic affairs, within the framework of the British commonwealth. The major question, or cluster of questions, in terms of which this evolution was measured and defined, concerned the conduct of the empire's foreign relations – in particular, the dominions' role and responsibilities in what had hitherto been accepted as a united, undifferentiated imperial foreign policy. It is this general area that I am principally concerned with in this study, with an emphasis not only on matters of foreign policy as such, but also on the equally significant problems of communications and consultation between Britain and the dominion governments.

The primary relationship I wish to examine, as illuminating these various aspects of the general inquiry, is that between Britain and Canada. Canada, the senior partner in the imperial structure (until the 1907 Colonial Conference it alone carried the title ‘dominion’) was also the most advanced in terms of population and economic development.