This article uses a case study of a celebrated enterprise partnership in Ireland that broke down to get an insight into why such arrangements are hard to sustain. The argument of the article is that meaningful enterprise partnerships require trade unions and management to accept agency costs, which in practice involves management modifying their right to manage and unions accepting that issues normally addressed by the collective bargaining process may have to be delegated to the partnership arrangement. The evidence of the case study is that neither management nor unions were prepared to incur such costs. The case study suggests that the following trinity – meaningful partnership, full‐blown collective bargaining and management's right to manage is exceptionally difficult to operate at the same time.