There is widespread concern about the shortage of secondary school teachers in England. Recruitment to initial teacher training regularly fails to meet its intake targets. The secondary school pupil population is increasing. Teacher vacancies have risen, and more teachers are reportedly leaving the profession prematurely. Despite considerable investment in a wide range of initiatives, costing millions of pounds, the government has acknowledged that it has been unable improve the situation substantially. This paper presents time-series analyses of official data and documentary analyses of government publications. These suggest that teacher shortages are partly created by government policies themselves - including flaws in the selection system, and school funding system, the official extension of the education and training leaving age, and increases in the number of small schools. It is difficult when planning for teacher supply to anticipate the impact of such varied policy changes years ahead. Consequently, estimations of the numbers needed to be trained are hardly ever accurate. This paper suggests a reconsideration of the current selection processes for initial teacher training, independent review of the Teacher Supply Model, and a long-term approach to teacher supply planning, considering other policy changes in a more coordinated way.