Richard Titmuss's classic study of social policy during the Second World War, Problems of Social Policy, published in 1950, has exercised an enormous influence on historical accounts of the period. However, recently his interpretation has fallen out of favour with revisionist historians who have argued that he exaggerated the extent to which the artifical conditions of war provided a permanent basis for the creation of the welfare state in the postwar period, and the degree to which evacuation changed official attitudes to poverty. This article examines to what extent the evacuation of September 1939 led to a reassessment of the earlier achievements of the School Medical Service, and how far it illustrated opinion on the reform of welfare services. After briefly tracing planning and the arrival of the evacuees in the reception areas, it considers what the evacuation revealed about the School Medical service and the wider problems of child health in four areas head lice and skin disease, footwear and clothing, nutrition, and child psychology. It concludes that while there was not unanimity on the need for reform, the evacuation did lead to a major reassessment of the effectiveness of health services for schoolchildren and to significant policy changes.