The idea of zero-sum power can be seen to ignore the fact that power relationships are not hermetically sealed but are socially constructed, determined in large part by the operation of forces external to them. If A is a black woman manager, for example, and B a white male employee, the ability of A to control the actions of B will derive not just from her occupational status, but also in part from the wider structures of race and sexual inequality which characterise the social systems in which they both live and work. In a similar way the relationship between professional social workers and their 'clients' or service users can be understood as affected, not just by the influence of professionally-based power, but also by the operation of a
