In April, the European Court of Justice (ECJ) issued a judgment on habitats regulations assessment (HRA) in a case from the Irish Republic, People Over Wind and Sweetman v Coillte Teoranta.
Under the European Union habitats directive, local planning authorities are required to carry out HRAs to make sure plans or projects affecting sites in and around EU-designated special areas of conservation (SACs) or special protection areas (SPAs) have no harmful effects on them.
HRA has two stages – a screening stage and then a full "appropriate assessment". Established practice is that proposals aiming to mitigate any negative impacts of a proposed plan or project, such as suitable alternative natural greenspaces (SANGs), can be considered at the screening stage. If the promoter can persuade the decision-maker at this point that negative impacts will be mitigated effectively, the requirement for appropriate assessment is avoided.
But April's ECJ ruling states that mitigation proposals "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".
Commentators have expressed concerns that the test at the appropriate assessment stage is a more stringent one for applicants to meet than that of the screening stage.
Planning and infrastructure lawyer Angus Walker, a partner at Bircham Dyson Bell, said one aspect of the Airport NPS, published by the Department for Transport (DfT) last week, appears to run counter to the ruling.
The paragraph in question relates to how applicants promoting airport projects, who would use the fast-track development consent order (DCO) route for major infrastructure, should go about complying with HRA rules.
Paragraph 4.20 states:
"The applicant is required to provide sufficient information with their applications for development consent to enable the secretary of state to carry out an appropriate assessment if required. This information should include details of any measures that are proposed to minimise or avoid any likely significant effects on a European site. The information provided may also assist the secretary of state in concluding that an appropriate assessment is not required because significant effects on European sites are sufficiently unlikely that they can be excluded. If it is concluded there is likely to be a significant effect, or such effects cannot be ruled out (alone or in combination), an appropriate assessment is required."
Walker said that, to comply with the judgment, the word "not" should be inserted in the second sentence after "should" to make clear that, since the ruling, mitigation proposals should not be provided at this stage of the process. The secretary of state's consideration of whether an "appropriate assessment" is required constitutes the screening stage, according to Walker, but the ruling states that such considerations should form part of the "appropriate assessment" itself.
Walker said: "It means the wording is incorrect and is no longer compatible with the judgement."
However, he said the text was not "explicitly unlawful" because the NPS "only implies" that the secretary of state would take mitigation measures into account at the screening stage but does not say that he "will or must definitely do so".
Walker also said that any decision on DCO applications cannot contravene international obligations, including EU law, which "essentially overrides the wording of the NPS".
He said: "DCOs would have to abide by the court ruling rather than this element of the NPS."
The final wording of the NPS is also subject to a Parliamentary vote, Walker pointed out, which means the government could propose an amendment to the text before that point.
A DfT spokesman denied the paragraph contradicted the judgment. He said: "It sets out information which an applicant is required to provide, to enable the appropriate assessment to be carried out if required.
"As it states, the information may also be relevant in deciding whether such an assessment is required.
"The secretary of state would only use the appropriate information at each stage in the process, in line with the requirements of the Habitats Directive and relevant court judgments."
The ECJ ruling has already prompted concerns about the impact on local plans and planning applications that might require HRAs.
Last week, it emerged that the Planning Inspectorate (PINS) has written to planning inspectors to provide guidance on the issue, warning that both local plans and individual projects could fall foul of the ruling.
In May, a planning inspector beginning his examination of Central Bedfordshire Council’s local plan asked the authority to justify its submission in light of the judgment, warning that it may not be "legally compliant".
NOTE: this story was updated at 5pm on Wednesday 13 June to add a comment from the DfT