The relations prevailing in industrial enterprises at the time of the People's Republic of Poland were frequently dominated by a game of interest involving informal pressure groups, concentrated around assorted centres of power within the given enterprise. The presented study deals with the activity of such a group in the 1 May Works in Pruszków, which specialised in producing machine tools, during the 1966-1968 period. The author demonstrated the process of taking over the competence assigned to official centres of power within the enterprise by a group concentrated around the trade union leaders. He also discussed the abuse committed by the union activists within the Work Board, and presented the activity pursued by the same group outside the union; first and foremost, he analysed cases of embezzlement perpetrated while calculating the workers' wages for overtime. The article interprets the analysed phenomena as a consequence of several simultaneous factors. In the first place, it indicates the significance of the centrally steered economy and the ambiguity of ownership rights. Second, it stresses the importance of the political character of the enterprise and, finally, points out the impact of cultural determinants by referring to the category of 'immoral familism'.