Long‐term unemployment more than doubled during the United Kingdom's Great Recession. Only a small fraction of this persistent increase can be accounted for by the changing composition of unemployment across personal and work history characteristics. Through extending a well‐known stocks‐flows decomposition of labour market fluctuations, the cyclical behaviour of participation flows can account for over two‐thirds of the high level of long‐term unemployment following the financial crisis, especially the procyclical flow from unemployment to inactivity. The pattern of these flows and their changing composition suggest a general shift in the labour force attachment of the unemployed during the downturn.