Domestic and European guidance states that decision- makers ought to take the cumulative effects of development into account as part of any EIA screening decision. In the case of Commercial Estates Group Ltd v Secretary of State for Communities and Local Government, the court considered European guidance on EIA screening, which describes “cumulative impacts” as being “impacts that result from incremental changes caused by other past, present or reasonably foreseeable actions together with the project”. There is no guidance on the meaning of “reasonably foreseeable”. 

In this case, the screening decision concerned an application for a 150 home development within an area identified in the council’s draft Core Strategy as suitable for a Sustainable Urban Extension (SUE). The court was asked to consider whether the designation of the wider area as a SUE, and a rival developer’s application for planning permission to build out the entire SUE, meant that the development of the SUE was a “reasonable foreseeable action” that should have been taken into account in the screening decision.

The judge held that it was not necessary or desirable to define “reasonable foreseeable” in this context but that the threshold of likelihood would be significantly higher than when the term was applied to the law of tort.

The likelihood of the SUE proposals coming to fruition was held to be a planning judgement for the decision maker (in this case the Secretary of State), which the court could only interfere with if it were shown to be Wednesbury unreasonable. In this case, there were clear uncertainties as to whether the development of the SUE would come forward and the claimant had failed to show that the Secretary of State had acted unlawfully by excluding consideration of the SUE from the screening decision.