First published in 1983. This study draws upon empirical findings on party activists, members and voters. It examines the origins and nature of Labour’s crisis in the 1980s, showing how the split leading to the formation of the SDP was merely a manifestation of deeply rooted problems which went back many years. It argues that this crisis had three distinct but interrelated aspects: first, the ideological schism within the party, which had grown in intensity over time; second, the electoral crisis, which produced the worst electoral performance at the 1983 general election since 1918; and, third, the membership crisis arising from the fact that the party had been losing more than 11, 000 individual members per year on average since 1945. Using elite and mass surveys the book demonstrates the link between these crises and Labour’s policy performance in office set against a background of rapid economic decline.