This history of National Accounts in Britain is done with two specific considerations in mind. First, the role of the economist John Maynard Keynes—as theoretician, compiler, supporter and user—is addressed. This role is substantial and has been greatly misunderstood or misrepresented by a large part of the literature. Second, the pioneering contributions made at the start of the 20th century by Alfred Flux, Arthur Bowley and Josiah Stamp, and later by Colin Clark, are detailed. The debates between these men mark the emergence of National Accounts as a serious discipline. Their work was supported by the earlier theoretical contributions of Alfred Marshall, and by practical developments, in particular the instigation of a Census of Production in 1907. Taken together, the two considerations tell a good part of the story of the emergence of National Accounting on the world stage.