Anonymized Legal Summary

Factual and Procedural Background

Judge Sales (with whom other Justices agreed) delivered the opinion on an appeal raising two issues of planning law at the intersection of environmental protection and large-scale residential development. The environmental concern was the introduction of phosphates from the proposed development into water systems feeding a protected Ramsar site (“the Ramsar site”).

The Appellant (a developer) seeks to construct a mixed-use scheme including approximately 650 dwellings, commercial and community uses, a primary school, and associated infrastructure on land in The City within the catchment of a river that ultimately feeds the Ramsar site. Excess phosphates risk eutrophication and ecological harm.

On 22 December 2015, the local planning authority (“the Council”) granted outline planning permission subject to 19 conditions. A site-wide surface water strategy had to be agreed before any reserved matters approval (discharged on 5 December 2016). The development was to proceed in eight phases.

In June 2020, the Council granted reserved matters approval for Phase 3 (circa 190 dwellings), subject to ten conditions, including pre-commencement conditions on tree protection, surface water drainage details, and a construction environmental management plan, plus conditions on infrastructure, a cycleway and footpath network, and materials.

On 17 August 2020, Company A issued new scientific advice citing the Dutch Nitrogen judgment, recommending that before determining a planning application that may add phosphates within the catchment for the Ramsar site, authorities should undertake a Habitats Regulations assessment and only grant permission if no adverse effect on site integrity is ascertained. It identified a “nutrient neutrality” approach as likely robust. Company B indicated mitigation opportunities near the Ramsar site were very limited, risking blockage of development.

On 9 June 2021, the Appellant applied to discharge several conditions attached to the Phase 3 reserved matters approval. The Council withheld approval, relying on national planning policy (para 181 of the National Planning Policy Framework (NPPF)), asserting that an “appropriate assessment” would be required before discharging those conditions (Issue 1).

On 5 April 2022, the Appellant appealed under section 78 of the Town and Country Planning Act 1990 due to non-determination. The Council resisted, relying on the NPPF and Company A’s advice. It issued a “shadow” appropriate assessment for Phase 3, concluding adverse effects on the Ramsar site could not be excluded and calculating a phosphorus load of 41.19 kg/year with no mitigation.

An Inspector dismissed the appeal on 24 November 2022, holding that the NPPF policy applied at the discharge-of-conditions stage, that Ramsar sites should receive protection equivalent to “European sites”, and that regulation 63 of the Conservation of Habitats and Species Regulations 2017 required an appropriate assessment. The Inspector rejected the Appellant’s contention that national policy could not introduce a new requirement after outline permission and reserved matters approval had been granted.

The Appellant’s statutory review under section 288 of the 1990 Act was dismissed by the High Court. The Court of Appeal dismissed a further appeal, agreeing with the High Court that regulation 63 applies at the stage of discharging conditions and that para 181 of the NPPF was a material consideration connecting the discharge decision to protection of Ramsar sites. The Appellant appealed to this court.

Legal Issues Presented

1. Whether, on the proper interpretation of the Habitats Regulations, an “appropriate assessment” under regulation 63 is required before a local planning authority decides to discharge conditions requiring approval of reserved matters in a grant of outline planning permission (Issue 1).
2. Whether, after the grant of outline planning permission, national policy (NPPF para 181) and subsequently issued scientific advice can lawfully affect the exercise of powers to approve reserved matters/discharge conditions such that an appropriate assessment equivalent is required for a Ramsar site (which is not a “European site” under the Habitats Regulations) (Issue 2).

Arguments of the Parties

Appellant’s Arguments

• Issue 1: The Habitats Regulations apply via regulation 70 at the grant of planning permission (including outline permission) but do not extend to the discharge of conditions or approval of reserved matters. Regulation 63 does not cover the discharge stage; a purposive approach and precautionary principle cannot override the clear text.
• Issue 2: Because a Ramsar site is not a “European site,” there is no legal requirement for an appropriate assessment at the reserved matters/discharge stage. Phosphate generation falls outside the scope of the specific conditions at issue and is therefore not a material planning consideration for their discharge. National policy (NPPF para 181) cannot convert an irrelevant consideration into a relevant one or override rights conferred by the outline permission.

Respondent Secretary of State’s Arguments

• Issue 1: Regulation 63 is framed in general terms and, read purposively with ordinary domestic interpretative principles and in light of the precautionary principle, applies at the reserved matters/discharge stage where the decision authorizes implementation.
• Issue 2: National policy in para 181 of the NPPF is a material consideration due to the nexus between discharging conditions (authorizing development) and preventing harm to protected sites; the policy does not displace habitats legislation but sets equivalent protection in planning decision-making for Ramsar sites.

The Council’s Position

• Relied on para 181 of the NPPF and Company A’s advice to require an assessment before discharging conditions, publishing a shadow assessment that could not exclude adverse effects and quantifying phosphate loading with no mitigation.

Intervener’s Submissions (Company B)

• Mitigation options near the Ramsar site are very limited, so following Company A’s approach risks blocking development in the locality.

Table of Precedents Cited

Court’s Reasoning and Analysis

Issue 1: Interpretation of regulation 63 of the Habitats Regulations

• The Court affirmed the Court of Appeal’s interpretation that regulation 63 applies at later stages in a multi‑stage planning process (such as approval of reserved matters or discharge of conditions) where the decision would authorize the project to proceed.
• Using ordinary domestic principles of statutory interpretation (purposive approach; reading text in its legislative context and in light of purpose), the Court emphasized the Regulations’ protective objective and the embedded precautionary principle.
• Regulation 63(1) uses deliberately broad language—“before deciding to undertake, or give any consent, permission or other authorisation for, a plan or project”—which is not confined to the initial grant of planning permission. The heading “General provisions for protection of European sites” and the structure reinforce general application.
• Regulation 62(1) does not limit the assessment provisions exclusively to the grant stage; instead, it recognizes the general requirements of regulations 63 and 64, with specific qualifications only for matters “specified” in Chapters 2 to 7. Later stages of a multi‑stage process are not so specified, leaving regulation 63 with general effect.
• Reading the Regulations otherwise would undermine their protective purpose and the precautionary principle where, for example, oversight or new science arises after outline permission. Properly construed, regulation 63 applies before a later-stage authorisation that would allow implementation.
• The Court endorsed prior domestic authority (including No Adastral New Town, Wingfield, and Swire) on this point. It was unnecessary to resort to EU interpretative doctrines because ordinary domestic tools, including purposive construction, suffice to reach the same conclusion.

Issue 2: Effect of outline planning permission and national policy (Ramsar sites)

• The Court allowed the appeal on Issue 2. It held that the courts below erred by according a national policy statement (NPPF para 181) the same force as a legal rule comparable to regulation 63 in the context of discharging conditions attached to reserved matters under an outline planning permission.
• Once planning permission is granted—whether full or outline—rights are conferred on the developer under the planning legislation. Those rights are not defeasible by subsequent shifts in general government policy or emerging scientific advice. Revocation or modification requires statutory procedures and may entail compensation.
• With outline permission, the permission is conditional, but the conditions are legally binding and delineate the matters on which further approval is required. Decisions to approve reserved matters or discharge conditions must be taken “within the terms of the condition” and cannot be used to revisit foundational points settled at outline stage or to import unrelated policy objectives.
• National planning policy (including NPPF para 181) is undoubtedly a “material consideration” when deciding whether to grant permission in the first place, and may be relevant to statutory powers concerning the timing of outline permissions. But after outline permission is granted, a policy cannot be invoked to override or dilute the rights the permission confers or to widen the scope of an existing condition.
• Here, the Council and the Inspector used para 181 and Company A’s advice to require an assessment effectively equivalent to regulation 63 before discharging sub‑conditions that were not directed to phosphate generation, potentially negating the development permitted in principle. The planning legislation provides no power to achieve that result via discharge decisions for a Ramsar site (which is not a “European site” under the Habitats Regulations).
• The Court distinguished authority indicating that, when discharging one condition, an authority may consider coherence with other conditions of the same permission; that limited principle does not permit importing new environmental policy requirements unrelated to the condition’s subject matter.

Holding and Implications

Holding: The appeal is DISMISSED on Issue 1 and ALLOWED on Issue 2.

Implications:

• For European sites, regulation 63 of the Habitats Regulations applies at later stages of a multi‑stage planning process (including approval of reserved matters and discharge of conditions) where the decision authorizes implementation.
• For Ramsar sites (which are protected by national policy, not by the Habitats Regulations), national policy such as NPPF para 181 cannot be used, after outline planning permission has been granted, to expand the scope of conditions or to require an assessment equivalent to regulation 63 when discharging conditions that do not encompass that subject matter. The direct effect is to confine discharge decisions to the terms of the permission and its conditions. No broader precedent is set beyond the application of existing principles regarding the limits of policy after the grant of permission.