The relationship between trade unionism and working-class solidarity has always been difficult. While an important part of the discourse of trade unionism has been anchored in a claim to represent the interests of workers as a whole, the historical role of unions as agents of working-class solidarity and unity is ambiguous. The multiple challenges to trade union solidarity that have emerged are complex and manifold. Structural changes also undermined the traditionally strongly unionised sectors of advanced capitalist economies such as heavy industry and manufacturing. Non-unionised sectors employing many more part-time workers in small establishments and service occupations constitute the fastest-growing segments of the economy. Trade union solidarity in the 1980s was further undermined by a general weakening of the authority of national union leaderships and centralised union confederations and growing conflict between national and local levels of unionism.