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People Over Wind and Sweetman - project design v mitigation – recent CJEU case muddies the waters

10 May 2018

This article is taken from May's public matters newsletter. Click here to view more articles from this issue.

A recent decision at the Court of Justice of the European Union (CJEU) in the matter of People Over Wind and Sweetman v Coillte Teoranta (C-323/17) has potentially altered the current UK position in relation to appropriate assessments under the Habitats Directive 92/43/EEC.


The Sweetman case concerned the decision to allow the laying of cables across two European special areas of conservation (SACs) (both in the Republic of Ireland). The cables are intended to connect a wind farm to the electricity grid and concerns have arisen that the plan may have a significant impact on a protected species of freshwater pearl mussel.

Under Article 6 of the Habitats Directive 92/43/EEC (the Directive) planning permission can only be granted if:

(a) There is no impact to the protected area [SAC], either by reason of nature of the plan or where specific preventative or mitigation techniques are employed to protect them, or

(b) Where there is a risk to the special area [SAC] and no mitigation can make it acceptable in terms of the Directive permission can only be granted where there are reasons of overriding public interest (including social or economic matters) and Member States shall take all compensatory measures necessary to ensure the coherence of Natura 2000 is protected.

The developer sought planning permission which was subsequently granted. The dispute related to the laying of cables where Coillte, a company owned by the Irish State, instructed consultants to complete a screening report to identify whether there were any risks to the river and or freshwater pearl mussel. The report concluded:

"(a) in the absence of protective measures, there is potential for the release of suspended solids into waterbodies along the proposed route, including direction drilling;

(b) With regards to the [pearl mussel], if the construction of the proposed cable works was to result in the release of silt or pollutants such as concrete into the pearl mussel population area of river… there would be a negative impact on the pearl mussel population. Sedimentation of gravels can prevent sufficient water flow through the gravels, starving the juveniles of oxygen."

The Irish Court heard that the species is nearing extinction with as low as 300 individuals left, having not reproduced itself since 1970 due to the vulnerability of juveniles to sedimentation.

Nonetheless, it was concluded by the screening report that appropriate assessment under the Directive was not required because of the protective measures that had been built into the work design of the project. The protective measures consisted of a construction methodology to control surface run off into watercourses.

The question considered by the Centre Européen de Coopération Juridique (CECJ) was:

‘Whether, or in what circumstances, mitigation measures can be considered when carrying out screening for appropriate assessment under Article 6(3) of the Habitats Directive’.


The CECJ highlighted that the Directive does not refer to ‘mitigation’; only conservation, prevention and compensation. The CECJ therefore interpreted ‘mitigation’ to mean:

"(26)… measures that are intended to avoid or reduce the harmful effects of the envisaged project on the site concerned".

In considering the requirements for appropriate assessment under the Directive, the CECJ concluded that the only requirements were that:

  • the plan or project is not necessary for the management of the special protection area
  • it must be likely to have a significant effect on the site.

Therefore, in quite resounding terms, the CECJ concluded that the very fact mitigation was required evidenced that the plan or project would significantly affect the special protection area. In such a scenario, an assessment should be undertaken so that the adequacy of mitigation measures could be considered with the benefit of a full appropriate assessment (which would provide significantly more information to the decision maker).

The CECJ concluded that:

“(37)… taking account of such measures at the screening stage would be liable to compromise the practical effect of the Habitats Directive in general, and the assessment stage in particular, as the latter stage would be deprived of its purposes and there would be a risk of circumvention… which constitutes… an essential safeguard provided for by the directive.” (Emphasis added)

Impact on the UK

In quite the opposite frame of mind, the UK has previously followed case law as set down in R (on the Application of Hart DC) v Secretary of State for Communities and Local Government [2008] EWHC 1204 (Admin) which concluded:

“(61) … if the competent authority is satisfied at the screening stage that the proponents of a project have fully recognised, assessed and reported the effects, and have incorporated appropriate measures when deciding whether an appropriate mitigation measures into the project, there is no reason why they should ignore such measures when deciding whether an appropriate assessment is necessary… as a matter of common sense, anything which encourages the proponents of plans and projects to incorporate mitigation measures at the earliest possible stage in the evolution of their plan or project is surely to be encouraged.” (Emphasis added)

The interpretation of the Directive, as incorporated into UK law by the Conservation of Habitats and Species Regulations 2017, may have a significant effect on developers and in reality, could be quite difficult to implement, leading to a substantial increase in the number of appropriate assessments required.

Primarily the issue relates to the definition of ‘plan or project’ as used by the CECJ in People Over Wind and Sweetman. The Sweetman case implies that 'plan or project' does not include mitigation measures built in and only relates to the core intention of the plan or project.

In the Sweetman case, the court’s position is understandable (indeed it is in my opinion the right decision) considering the acknowledgement that the plan or project would risk a critically endangered species and the description of the mitigation as ‘protective measures that have been built into the work design of the project’. It is logical that these protective measures are considered further by away of an appropriate assessment in order to better understand the effectiveness.

However there is a difference between protective measures and the way that the project is structured. In some cases it will be easy, for example when acoustic screens are installed to reduce the effects of noise on sensitive habitats; this is likely to be mitigation.

The situation is more difficult when a project has been structured (for example it is carried out only at certain times of the year or in certain places) so as to avoid any impact on interest features. Does this account as mitigation, or should an appropriate assessment be undertaken?

On the one hand it is arguable that the more information provided the better in order to allow a fully informed decision to be made. However the disadvantage is that the 2017 Regulations create an unnecessary burden and cost on those undertaking plans and projects.

For example, an intention to build a bridge over water in which a protected species of bird feeds: mitigation may necessarily be to make the bridge design higher to ensure that there is no restriction on the bird’s access to the water. To remove the mitigation would be to remove the very design of the bridge and consequently the plan may become impossible to consider.

It will be interesting to see how such an interpretation unfolds in practical terms.

In my experience screening decisions which consider mitigation measures effectively end up as appropriate assessments due to the amount of information required to ensure that there is no likely significant effect. In my opinion we are more likely to see plans and projects subject to appropriate assessment - however public bodies will need to exercise their discretion as to whether something is a plan or project or mitigation for a plan or project. As is always the case, a well-reasoned note of the reasons for any determination will assist in in successfully defending any claims. It is also very likely that future decision of public bodies will be subject to judicial consideration - hopefully this will provide clarity rather than muddy the waters further.

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The content on this page is provided for the purposes of general interest and information. It contains only brief summaries of aspects of the subject matter and does not provide comprehensive statements of the law. It does not constitute legal advice and does not provide a substitute for it.

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