The Merseyside Structure Plan established the twin policies of investment in the inner areas and restrictions on peripheral growth as the basis for urban regeneration in Liverpool. By the 1980s economic development, urban regeneration and environmental improvement were the dominant planning concerns in Liverpool. To the extent that population gain is evidence of regeneration it can be supposed that all the cities have experienced some regenerative effect during the last decade but that its extent has varied between places. Although the plans and policies of the 1960s were published long before the emergence of the environmental agenda, planners had traditionally embraced a concern for 'amenity' and 'efficiency' in town design that naturally led them towards many of the goals of sustainable development. Investment in major infrastructure projects such as airport developments, inter-urban highways and power stations almost seemed to go ahead regardless of the planning system.