Three main models have been developed to explain who exercises power in the UK - the pluralist model, the elite model and the Marxist model.

According to the pluralist model, power is exercised by the mass of the population, rather than by a small elite group. This conclusion is derived from two main arguments. First, pluralists note that if a majority of people do not like what their representatives are doing, they can vote them out of office at the next election. Representatives, therefore, have to act in a way that is pleasing to the majority. Second, pluralists consider voting to be of only irregular significance. General elections occur periodically and individuals are asked to vote for packages of policies put together by political parties. Therefore, voters do not have an opportunity to wield influence on the specific issues that concern them; so pluralists claim that people are able to exercise power between elections by joining interest groups - such as political parties, trade unions and other pressure groups. Group activity, they argue, is vital to the successful functioning of the political system.

What matters to pluralists about the distribution of power in society is not that it is uneven, but that it is widely dispersed rather than concentrated into the hands of the few. It also follows that, according to the pluralist model, the state acts impartially - responding to the demands of different popular pressures. No single group can possibly dominate in society since, for every force exerted by one group, there is an equal and opposite force exerted by other groups. Pluralists argue that such a system is healthy because it encourages political participation, it ensures that people can exert influence over decision makers, it ensures that power is dispersed rather than concentrated into the hands of a few and, at the same time, it allows the view of minority groups to be voiced.