This paper examines the effects of union change in Britain on changes in earnings dispersion 1983-1995. We investigate not only the decline in union density but also the greater wage compression among unionised workers, as well as changes in union density across skill groups. For the private sector, we find that deunionisation accounts for little of the increase in earnings dispersion. What unions have lost on the swings (lower density), they have gained on the roundabouts (greater wage compression). But for the public sector we find strong effects, because unions are increasingly organising the more skilled. This change in the character of public sector unions means that they no longer reduce earnings variation nearly as much as they once did.