Originally an ecologist, Bill has worked, lectured and published widely on environmental impact assessment (EIA) for more than 22 years. He has worked as a practicing ecologist, in consultancy, academia and in the voluntary sector.

His experience lies in the development and application of EIA/SEA/SA legislation in the European Union, assessment procedures, methodologies, and public and NGO participation. He has been an expert advisor to the EC, the European Environment Agency, the Irish Government, CPRE and the National Trust; was a long-standing member of the Environment Agency (and formerly NRA) Thames Regional Committees; and has been involved in various committees of the International Association for Impact Assessment (IAIA). He has also provided expert evidence to public inquiries and international hearings. 

Bill has managed major studies for the European Commission DG Environment on SEA and Integration of the Environment into Strategic Decision-Making (2000/01); on the relationship between the EIA and SEA Directives (2004/5); and led an international team in the development and application of sustainability assessment of biodiversity management scenarios for declining agricultural areas in upland Europe (EU 5FP, 2002-5).  Recent and current activities include research and SEA in Scotland and Wales, research in Ireland on the Water Framework Directive and its relationship with other environmental Directives, research for the European Environment Agency on scenario and foresight studies, and sustainability appraisal for the Greater London Authority on the GLA's proposed Water Strategy and Climate Change Adaptation Strategy.