A wide range of economic and social forces have combined to influence the nature of the urban retailing system in the post-war period. The impact of hypermarkets and superstores and purpose-built shopping centres in outlying locations has been a dominant issue of retail planning in UK for the last two decades. No other country in Western Europe has sought to contain the process of decentralization to the same degree as in Britain. The procedure for the preparation of town centre plans was established by the 1947 Town and Country Planning Act which gave local authorities power to obtain land through compulsory purchase and to designate comprehensive development areas. By the mid 1960s however there was a marked change in the nature of shopping provisions envisaged in the development plans as private developers pressed for the introduction of new enclosed centres, similar to those that had been built in suburban areas of North America.