Despite the fact that SEA has been a legal requirement since 2005, there has been relatively little commentary or practice that has emerged on what authorities are required to do with the output of the SEA process. As a result, this area is relatively untested in the context of major infrastructure development, and particularly in the area of nuclear/energy planning. The key question remains exactly how, if at all, local authorities should aim to integrate the results of the SEA process, and the conclusions of the Environmental Report, with the subsequent process of granting individual development consents for projects.

Even outside the energy sector there is surprisingly little written guidance on this and indeed very little written legal opinion on the appropriate use of SEA materials at the development consent stage (such challenges relat­ing to SEA that we have seen relating to the policies themselves, not the subsequent reliance upon them). This has the somewhat unfortunate result of potentially leaving authorities with the mistaken belief that the SEA process is an exercise with no real end. Nonetheless, this is not a safe assumption to make and does not sit at all comfortably with the express objective of the SEA Directive to ensure that environmental considerations are fully integrated in the development process. The way in which the SEA output material influences project-level development control decisions will be how, in practice, the process of SEA influences development on the ground with a view to promoting sustainable development.

In principle, the answer to this problem is relatively simple — when a developer makes a project-specific development consent application which relies upon, or perhaps more widely just bears upon, any ‘plan or pro­gramme’ which has been subject to the SEA regime, it will be important for the determining authority to at least make references to the Environmental Report, the output of the SEA regime which should have already been completed. The usual method by which this is effected is through the detailed project-level Environmental Impact Assessment (EIA). There are undoubtedly some areas of overlap between the SEA process and the EIA process, but the Commission of the European Union has broadly distinguished the two on the basis that SEA applies ‘upstream’ to certain public plans and programmes, while EIA applies ‘downstream’ to certain public and private projects (European Commission, 2009, paragraph 3.5).