This article shows that variations in how two UK governments justified contracting-out (issue framing), combined with shifting sector-derived incentives for union activism (sector character), can help explain the extent of contracting-out. Janitorial service, an activity of the UK government that should have been ‘low hanging fruit' for its prolific reformers, proved difficult to contract-out for Thatcher's New Right Conservatives, but easier to contract-out for Blair's New Labour. The New Right government framed contracting-out narrowly, as merely an improvement in operational efficiency, and its reform faced unions that stood to lose a great deal from movement of janitorial jobs to private firms. In contrast, the New Labour government framed contracting-out broadly, as a means to efficient social justice, and faced unions with low stakes in government janitors. As a consequence, UK government units could expect lower benefit and higher cost from contracting-out janitors under Thatcher than they would under Blair.