and, directly and through its impact on economic growth and development. Ageing increases the number of households and therefore per capita electricity consumption. Migration also affects the need for new capacity investment in production transmission and distribution. In the case of land transport, Stambrook points out that, together with GDP growth, population growth is the most important determinant of growth in the demand for infrastructure. He also points to the significance of population density, notably for the development of high-speed rail (HSR). However, he sees population ageing as having only an indirect effect, i.e. as putting pressure on health care systems and leading to many competing policy pressures for limited public funds - especially with the apparent "cap" on taxpayer willingness-to-pay. This position contrasts interestingly with the view expressed in other studies where population ageing is perceived to have an important impact on peak infrastructure use, a major determinant of infrastructure requirements. Demography will also be a major determinant of the demand for water infrastructure. In developing countries, the rapid growth of population in urban areas, coupled with the pressures of economic growth, will give rise to considerable demands for water services both to provide industry with a base resource and also for the survival of the population. Given the low level of income of the majority of the population, the challenge will be to provide and extend a basic level of service to the burgeoning population centres at an affordable cost to both government and citizens alike. In the developed world, shifting patterns of human settlement may put sustained pressure on freshwater resources in some regions, possibly leading to tensions between urban and agricultural communities over priority setting for water use. However, the challenges are more likely to arise as a result of the consequences of population ageing (and the attendant increase in the number of households) rather than the need 