This thesis examines processes of political change in the Murton miners' and mechanics' branches of the National Union of Mineworkers (NUM) between 1978 and 1988. During this period both branches swung from the right of the NUM's political spectrum to the left. Recent debates in human geography - and the social sciences more generally - have drawn attention to the importance of place in analysing social developments. However, a review of the literature reveals a surprising lack of detailed studies undertaken at the local level. In order to understand the constraints under which events at a local level take place, it is necessary to place them in context. The coal industry is therefore located at the centre of a complex set of institutionalised relationships between capital, labour and the state known as the "post war settlement" (PWS). As economic crisis deepened in the 1970's, the PWS came under attack. In the coal industry this led to the progressive destabilisation of a characteristic "indulgency pattern" which had built up in the post war years. At Murton, this destabilisation created the room for left wing activists to build support in miners' and mechanics' branches. However, their impact was unevenly distributed among the workforce because miners from different backgrounds were affected in different ways by the crisis in the industry. Cleavages of age and residence led to significant differences in miners' and mechanics' understanding of the crisis facing the industry. This thesis examines the interaction between local union branch leadership, the changing situation in the coal industry, and divisions within the workforce during three distinct periods: from 1978 until the eve of the 1984/5 strike; the strike itself; and the period since the strike until the end of 1988.