This paper explores the idea of 'legal mobilisation', focusing particularly on the use of individual employment rights by unions to pressurise employers and to galvanise support amongst members for action on key workplace issues. Literature from north America suggests that the law can provide inspirational effects, crystallising a sense of injustice and highlighting the availability of redress, and radiating effects, where positive outcomes are diffused with a view to changing employer behaviour or mobilising broader groups of workers. Data from two critical case studies in the UK, however, highlight tensions in strategies of this kind. Minimal and complex statutory provision makes the law a cumbersome instrument to use in organising strategies. Legal mobilisation is likely to remain as a pragmatic tactic in specific circumstances, but more systematic adoption seems unlikely in the British context.