Mitigation measures must be IGNORED when carrying out screening assessments under the Habitats Directive

18 May 2018

Planning and Environment


In an important judgment which will have ramifications for all involved with proposed development near to European Sites (i.e. SACs, SPAs), the CJEU has ruled that mitigation measures cannot be taken into account when carrying out a screening assessment to decide whether a full ‘appropriate assessment’ is needed under the Habitats Directive.

The judgment in People Over Wind v Coillte Teoranta C-323/17 is important because it is inconsistent with judgments of the High Court, Court of Appeal and Supreme Court on this same point. It also opens up an important point of difference between the procedures for Habitats Directive assessments and environmental impact assessments.

The position in domestic law

In R (Hart DC) v SSCLG [2008] EWHC 1204 (Admin) the High Court held that mitigation measures can and should be taken into account in screening assessments for the purposes of the Habitats Directive. Sullivan J thought there was no sensible reason for ignoring mitigation measures when they had been incorporated within a planning application, and it would be ‘ludicrous’ to disaggregate the component parts of the proposal in order to carry out screening. This would create an unnecessary “legal obstacle course”.

The judgment in Hart has been endorsed in many subsequent cases. Most notably, the inclusion of mitigation measures at the screening stage was accepted by the Supreme Court in Champion v North Norfolk DC [2015] UKSC 52 (para 42).

The CJEU’s judgment

The CJEU’s judgment is short and to the point. The Court observed that the fact that mitigation measures were taken into account in determining whether an appropriate assessment was necessary “presupposes that it is likely that the site is affected significantly and that, consequently, such an assessment should be carried out” (para 35). In the CJEU’s view, “a full and precise analysis of the measures capable of avoiding or reducing any significant effects on the site concerned must be carried out not at the screening stage, but specifically at the stage of the appropriate assessment” (para 36). Otherwise there would be a risk of compromising the Habitats Directive in general “and the assessment stage in particular, as the latter stage would be deprived of its purpose and there would be a risk of circumvention of that stage” (para 37).


  • This is a significant judgment which will inevitably be followed by the UK courts when the matter is next raised in domestic litigation, although it will of course take time for that position to be confirmed. But the direction of travel is very clear.
  • The upshot of the judgment is clearly that a full ‘appropriate assessment’ will be required in many more cases than at present, as it will not be possible to ‘screen out’ applications by relying on mitigation measures which have been designed into the proposal. By ‘mitigation measures’, the CJEU confirmed that it was referring to measures “intended to avoid or reduce the harmful effects of the plan or project on that site”. Therefore, this judgment applies to measures which would prevent harm arising in the first place as well as measures to mitigate harmful effects that would otherwise occur.
  • The judgment also represents a new and important point of distinction between Habitats Directive assessments and EIA, which could prove to be a trap for the unwary. Mitigation measures still can and should still be taken into account when screening for EIA.
  • Although the position is not yet confirmed in the domestic legal system, developers and LPAs will need to be aware of this judgment and would be well advised to adopt a cautious approach and to exclude mitigation measures from any Habitats Directive screening assessments going forward. A failure to do so will provide a fruitful ground of challenge for those objecting to applications and decisions. Mitigation measures will of course be taken into account in the full ‘appropriate assessment’, in order to determine whether the project as a whole will have an adverse effect on the integrity of a European site.

Emma Dring is a member of the planning team and has experience of advising and representing clients on issues relating to the Habitats Directive (including appearing in the High Court and Court of Appeal in No Adastral New Town Ltd v Suffolk Coastal DC [2015] EWCA Civ 88, which considered issues around mitigation measures and screening).