Social enterprise is a contested concept which has become a site for policy intervention in many countries. In the UK the government has invested significant resources into social enterprise infrastructure, partly to increase the capacity of social enterprises to deliver or replace public services. Government publications show the number of social enterprises to have increased from 5,300 to 62,000 over a five-year period. This paper explores the myth of social enterprise growth in the UK through a methodological critique of the four government data sources used to construct and legitimise this myth. Particular attention is paid to how political decisions influence the construction of evidence. We find that growth is mainly attributable to political decisions to reinterpret key elements of the social enterprise definition and to include new organisational types in sampling frames.