It is widely agreed that the early years are a particularly important time for efforts to increase social mobility, because a good deal of inequality is already apparent by the time children start school, and because children’s development may be less amenable to change after they enter school. But it is less clear how much policies can reduce inequality in the early years, or what policies might be most effective, given the multiple influences on development in the early years and given the complex effects of policies. In this paper, I review what we know from research about what affects development in the early years and examine the current UK policy framework in light of that research. I then make recommendations for priorities for next ...