This thesis explores the impact of one particular change in industrial conflict legislation in the 1980s: that is, the requirement for trade unions to hold ballots before industrial action. It does so by analysing the results of an extensive postal questionnaire survey, covering 846 negotiators in 25 unions. This was part of a wider research project on the impact of changes in the law, incorporating interviews with employers and senior National Officers of trade unions. The conclusions in the thesis also draw on these findings. The fieldwork was carried out in 1991 and 1992. It took into account a number of modifications - notably in 1988 and 1990 - to the original balloting provisions in the 1984 Trade Union Act. The thesis provides an analysis of the impact of the industrial action balloting requirement on trade union practices and the role of balloting in negotiations, looking beyond injunctions and high profile court cases. The thesis is primarily concerned to examine the impact of ballots on the processes of collective bargaining. It concludes that the effects of the 1984 balloting laws, including their amendments, were far more complex than anticipated or claimed by the Government. Internally industrial action ballots were accommodated by trade unions into existing consultation processes. The potential for ballots to modify substantive decisions within trade unions, by centralising and formalising decision making, was thereby limited. Amendments to the balloting laws increased the difficulties for trade union negotiators in accommodating ballots in the collective bargaining process. Trade union negotiators, however, sought by and large to conduct industrial action in accordance with the balloting laws and, despite an increasingly restrictive legal framework, there was a widespread perception among trade union negotiators in the early 1990s that this could bring negotiating advantage. Generally, it is apparent that industrial action ballots were one aspect of a complex process of sometimes radical change in industrial relations throughout the 1980s.