A sharp rise in the number of pupils or students reaching a particular stage in the education system at any one time. It was coined as a term to describe the demographic phenomenon following the end of the Second World War, when birth rates rose sharply, creating a succession of unusually large cohorts of pupils which proceeded through the various stages of schooling and higher education in the 1950s and 1960s. The existing number of teachers and the available classroom space in state schools was insufficient to meet this demand. However, when the bulge had moved through the system and the number of children entering compulsory education began to fall, schools found themselves with a surplus of teachers, while local authorities were, in some cases, forced to close down schools for lack of pupils. Some educationalists saw this as an opportunity for introducing smaller pupil–teacher ratios for the benefit of the pupils; but in policy terms the problem was viewed as financial and addressed accordingly with a reduction in teaching posts and classroom space.