The role of master varies significantly between colleges of the same university, and even more so between different universities. However, the master will often have responsibility for leading the governing body of the college, often acting as a chair of various college committees; for executing the decisions of the governing body through the college's organisational structure, acting as a chief executive; and for representing the college externally, both within the government of the university and further afield often in aid of fund-raising for the college. The nature of the role varies in importance depending on the nature of the collegiate university. At loosely federated universities such as the University of London, each college is self-governing and the head of a college acts much like a vice-chancellor. At more centralised universities where colleges are not independent institutions, a college head will have much less power and responsibility.
Inasmuch as the colleges of the University of London operate as semi-autonomous universities, sharing certain student services and administrative facilities but undertaking independent teaching and research, the heads of these colleges have almost the same level of responsibility as a vice-chancellor of a non-collegiate university.
However, in addition to governing their own institutions, the heads of the colleges of the University of London are ex-officio members of the university's Collegiate Council, one of two major decision-making bodies in the central university.