The first half of the fourteenth century witnessed the culmination of the first of three great waves of population growth which may be discerned during the pre-industrial period. At the same time, the living standard of the mass of the population reached a nadir below which it was never again to fall, with a substantial proportion living at a level which was marginal for bare subsistence. England's population of four to six millions was, in fact, at least three, and possibly even four, times greater than it had been some two-and-a-half centuries earlier. The consequence of so great an increase in population, according to M. M. Postan, was that it ultimately brought about its own nemesis. An over-concentration upon grain production, coupled with deficient agricultural technology, led to soil exhaustion and the abandonment of land and thus to a real decline in agricultural production: a decline, moreover, which was exacerbated during the late thirteenth and early fourteenth centuries by a succession of bad harvests of which the worst – the so-called Great Famine – occurred in 1315–17. The latter event precipitated a major subsistence crisis from which the population never fully recovered. In Postan's view, therefore, when bubonic plague arrived in 1348–9 it struck a population which was already in decline.

Postan's neo-Malthusian explanation of events has found favour with a great many medieval economic and social historians. Indeed, insofar as it has met with serious challenge this has been directed less against the circumstantial nature of so much of his evidence than against his ascription of the role of prime mover to demographic trends.