The Government published its teacher recruitment and retention strategy in January 2019 in response to a growing teacher supply challenge in England. Four years since the publication of the teacher recruitment and retention strategy, and despite the increases in recruitment and retention that came about due to the COVID-19 pandemic, teacher supply in England remains in a perilous state. Failing to recruit and retain enough teachers has significant implications for school staffing and therefore for pupils' education and learning. This essay draws together the range of insights that the author has gained from a programme of research funded by the Nuffield Foundation. The essay discusses the implications of the research findings for teacher supply policy in England within the landscape in early 2023. The essay explores the key trends in teacher recruitment, retention and working conditions over the last decade, assessing what progress has been made in addressing the growing teacher supply challenge and where future policy attention could best be focussed to continue addressing the challenges.