By 1966 it had become clear that the doctrine of individual ministerial responsibility, which lay at the heart of the British constitution, had failed to evolve in order to meet the requirements of modern government. This thesis puts forward a review of the doctrine's operation and theoretical basis over a seventeen year period, starting with the advent of new organs of parliamentary scrutiny under the second Wilson Government. It is argued that individual ministerial responsibility can best be understood with reference to four distinct, yet interlocking elements. One of these, accountability, was the focus of significant change between 1966 and 1983. During these years, it was possible to discern the emergence of a new regime of parliamentary accountability. Within this, the traditional methods of scrutiny continued to operate, but they were joined by new Select Committees and the Parliamentary Commissioner for Administration. These new organs had the effect of increasing the quantity and enhancing the quality of scrutiny which could be brought to bear on ministers and civil servants. In a real sense, ministers became more accountable to Parliament for their role responsibilities, while the civil servants' accountability to their superiors in the administrative hierarchy, to their ministerial masters, and most importantly, to Parliament, was enhanced. In particular, the operation of the new Select Committees created a situation where the de lure statement of civil service non-accountability to Parliament came into obvious conflict with the emerging de facto accountability to this source. Individual ministerial responsibility remains a useful description of how British government is organised and operates. The doctrine should not be viewed as a constitutional myth, although one of its elements, sanctions, is nearer to myth than reality. The period 1966-83 witnessed no "revival" of this element, only a few false starts.