To analyse social alignments since 1918. Parliamentary constituency candidatures and votes for each election in the period 1918 to October 1974, plus census variables related to social class, religiosity, religious sect, industrial sectors, consumption (affluence) levels, socialized versus privatised consumption, unemployment, Welsh language, population density, etc. Census data was taken from the 1921, 1931, 1951 and 1966 census. The main files are arranged by 'constant units', i.e. groups of constituencies which in aggregate had approximately constant boundaries over the 1918-1974 period (or at least expanded their boundaries at a time when very few lived in the expansion zone, etc.). Please note: this study does not include information on named individuals and would therefore not be useful for personal family history research.