The thesis begins by considering the established political business cycle models. There are five such models: (i) the pure political business cycle; (ii) strong partisan theory; (iii) conventional weak partisan theory; (iv) rational partisan theory; and (v) the rational political business cycle. We consider carefully the assumptions upon which these models are based, particularly their modelling of the government's objective function. This function is typically characterised as either opportunistic or ideological. Only conventional weak partisan theory attempts to analyse the switch mechanism between opportunism and ideology. There is little empirical evidence to support the belief that either opportunism or ideology alone has consistently affected economic outcomes and general government expenditures in the UK. Therefore, we focus on the trade-off between opportunism and ideology and its effect on UK general government expenditures. We argue that in modelling the switch between opportunism and ideology we need to consider the components of a re-election index as well as a series of qualifying indicators. These combine to define values of a qualified differential. We, therefore, develop the partisan indicator model. We stress that political business cycle theorists need to consider carefully what is meant by politically expedient behaviour. The creation of cycles need not equate with political expedience. Our other main concern is the effect of economic and political interdependencies between nations, not only on the implications of established political business cycle models, but also on the partisan indicator model. Therefore, political business cycle theorists need to look at an internationalisation of the literature.