Changes in residential location: the single most important factor has been the widespreads ubu rbanization of population. Despite signs of growth in some inner-city areas related to gentrification and the arrival of immigrant groups, the overall metropolitan population trend has been one of decentralization. In general it has been the younger, richer and more mobile elements of society that have migrated to the suburbs to create new large sources of demand in areas where few shopping facilities had existed previously. An older poorer and less mobile population has been left behind in the inner city where their lower levels of purchasing power have been insufficient to support the surfeit of shopping facilities that remain. These changes have been most pronounced in the US city where the earlier pattern of retailing has been altered by the growth of new suburban and outlying centres and the decline of central shopping areas. In Britain by contrast strict planning controls have restrained the process of retail decentralization and where it has proceeded it has been mainly associated with convenience trades. 2 The growth of female employment: the fact that women now account for a significantly higher proportion of the total workforce than they did a quarter of a century ago has had two major implications for consumer behaviour - first, through the increased purchasing power created by additions to household incomes and secondly, through the time constraints imposed on shopping, particularly for women engaged in full-time work. The result has been an increase in bulk buying, especially for food, and a reduction in the frequency of shopping trips. This trend has been facilitated by the increased ownership of refrigerators and freezers. There has also been a rise in the proportion of shopping trips originating (and for lunchtime trips, ending) at the workplace.