Screening and mitigation measures

A recent decision of the Court of Justice of the European Union will have implications for all nationally significant infrastructure and other projects that could affect protected environmental sites, writes Angus Walker.

Certain sites around the country have a special EU level of protection and are known collectively as Natura 2000 sites, or sometimes by some of their sub-types, Special Protection Areas (SPAs – not obvious from the name but these are related to birds) and Special Areas of Conservation (SACs – which relate to other species and habitats). The latest iteration of transposition of the relevant directives into UK law is the Conservation of Habitats and Species Regulations 2017.

The case, known as ‘People Over Wind v Coillte Teoranta’ (I believe the first word of the defendant is pronounced ‘quill-cha), is an Irish case concerning an electricity cable to connect a wind farm, and its potential to affect two SACs, one of which contains a species of mussel (the Nore pearl mussel) that is at risk of becoming extinct. The full judgment can be found here, but here is a summary.

The mussels need clear water and so the deposit of any sediment was an issue. The developers obtained a screening opinion that this would not be a problem if specified ‘protective measures’ were implemented, set out in a Construction Environmental Management Plan (CEMP). The screening meant that the project did not need to go further along the process of analysing effects on the SPAs known as ‘appropriate assessment’.

The High Court of Ireland referred the following question to the CJEU: ‘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 CJEU answered bluntly that ‘in order to determine whether it is necessary to carry out, subsequently, an appropriate assessment of the implications, for a site concerned, of a plan or project, it is not appropriate, at the screening stage, to take account of the measures intended to avoid or reduce the harmful effects of the plan or project on that site.’

The main reason given was that ‘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’. Not really a reason, but a statement supporting the judgment.

This is at odds with a 2008 English case ‘Hart v Secretary of State for Communities and Local Government‘, where Mr Justice Sullivan said that ‘I am satisfied that there is no legal requirement that a screening assessment under Regulation 48(1) must be carried out in the absence of any mitigation measures that form part of a plan or project.’

The CJEU judgment has caused some consternation in environmental circles as it has overturned an issue that had been thought settled. Although it doesn’t necessarily mean projects being more likely to be refused, it does mean they may have to go further along the appropriate assessment flowchart before they can get consent (eg the one on page 4 of Advice Note 10) which may add to cost and time.

It might be the case that mitigation measures designed into the project in question could still be taken into account at the screening stage, as separate from mitigation measures added afterwards, and it would surely be unhelpful to discourage the incorporation of mitigation into design, sometimes known as ’embedded mitigation’. We shall no doubt see.

The takeaway from this is that if your project has one or more nearby Natura 2000 sites, you may need to take another look at what you took into account to decide whether it needed appropriate assessment – or if you haven’t got that far, you may need to take a slightly stricter approach. If you are opposing a project, then check what was done as it may not have been enough.

Angus Walker is a partner at Bircham Dyson Bell. He can be contacted on 020 7783 3441 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it . This article first appeared in Angus' blog on the Planning Act 2008 regime.