What Would the British Party System Look Like under Proportional Representation?

British debates over electoral reform are invariably debates about what party system would emerge. While there is agreement that proportional representation (PR) would boost the size of existing smaller parties, there is no consensus over the emergence and prospering of new parties. The main weakness in the British debate concerns the types of governments that would form under PR. Some believe the Liberal Democrats would be perennial kingmakers. Others suggest that a ‘progressive alliance’ on the centre‐left would sweep all before it. This article considers the experience of west European multiparty systems since the 1980s and argues that party system fragmentation and the growth of non‐centrist parties would characterise Britain under PR. Moreover, the pattern of overlapping centrist coalitions seen in Germany and Benelux would be unlikely to emerge in Britain. Instead, a two‐bloc system, common in Scandinavia and southern Europe, would most likely develop.