Introduction

The UK constitutes the paradigmatic case of a majoritarian democracy. As we have argued in Chapter 2, such a system discourages the rise of new challengers in the party system. This implies a greater stability of partisan configurations, but it does not mean that party systems are not subject to change. Under conditions of majoritarian democracies, the transformation of the party system is, however, more likely to involve the transformation of mainstream parties. As we have argued in Chapter 2, in majoritarian systems, the number of mainstream parties is more limited and, as a consequence, their internal composition is likely to be more heterogeneous than in proportional systems. New structural cleavages are likely to cut across the mainstream parties and to put them under great tension. The strain is expected to be particularly strong in the mainstream party that finds itself in the opposition. Such a party is likely to expand the scope of conflict on issues linked to the new cleavage, i.e. to adopt a more radical stance with regard to such issues. Therefore, in a majoritarian system such as the UK, shifts of power within mainstream parties are not only more likely to occur than in PR systems, but they also take on a much greater significance.

In the period covered by our project, two decisive shifts have occurred in each one of the major parties – the Conservative Party and the Labour Party – with far-reaching implications for the restructuration of the party system as a whole.