Theoretical approaches to collective action are many and varied. Part of the reason for the heterogeneity derives from the different definitions of collective action which have been adopted. For many social scientists, the term collective action encompasses an incredibly broad range of empirical phenomena - from raising an army to raising a barn’ (Marwell and Oliver, 1993:1) - whose common elements, these authors suggest, are mutual interests and the possibility of benefits from coordinated action. For those interested specifically in a political context, the term refers to a type of political action which consists principally of ‘working through organised or informal groups . . . to raise an issue’ (Parry, Moyser and Day, 1992: 52).