Background

CG Fry obtained outline planning permission in 2015 for 650 homes near Wellington in Somerset. Five years later, Natural England issued new advice on phosphate impacts affecting the Somerset Levels Ramsar Site. When the developer applied to discharge certain conditions attached to its reserved-matters approval, the council refused to do so, insisting that an “appropriate assessment” was required before the conditions could be signed off.

The developer appealed unsuccessfully through the planning and legal system until the case reached the Supreme Court earlier this year.

What the Supreme Court decided

The Court considered two main issues.

First, it agreed that the Habitats Regulations can, in principle, apply at later stages of a multi-stage planning process. Where a development may affect a European site – such as a Special Area of Conservation (SAC) or Special Protection Area (SPA) – an “appropriate assessment” may still be required when approving reserved matters or discharging pre-commencement conditions.

Second, however, the Court found that the same logic does not apply to Ramsar sites, which are protected through national policy rather than the Habitats Regulations. National policy cannot retrospectively reopen matters that were settled by the grant of planning permission. Once permission is granted, it creates a legal right to develop, subject only to the conditions imposed. Unless a matter was expressly reserved, it cannot later be revisited or expanded through new guidance or policy.

On that basis, the Court concluded that the council could not lawfully refuse to discharge conditions by relying on Natural England’s later phosphate advice.

Where this leaves matters

The ruling provides welcome clarity for Ramsar-only sites, confirming that councils cannot rely on national policy alone to impose new environmental obligations after permission has been granted.

However, for European sites – including Stodmarsh in Kent, the Solent, and parts of Norfolk – the position remains unchanged. The Habitats Regulations still apply, and appropriate assessments will continue to be required wherever potential impacts arise, even at the reserved-matters or condition-discharge stage.

In practice, this means that the judgment is only likely to assist in a narrow range of cases: those where a development affects a Ramsar site (and no SAC or SPA), and where a valid permission already exists without conditions covering nutrient impacts.

Where the Planning and Infrastructure Bill might take us

While the judgment settles the current law, the position may not remain static for long. The Planning and Infrastructure Bill (PIB), now before Parliament, could reshape the environmental assessment framework in two important ways.

First, it proposes to bring Ramsar sites within the Habitats Regulations, which would effectively reverse the short-term benefit that CG Fry has created for Ramsar-only developments.

Second, the Bill introduces a new system of Environmental Outcomes Reports, intended to replace the existing environmental assessment processes. Depending on how this is implemented, it could significantly streamline or even replace the need for traditional “appropriate assessments” under the Habitats Regulations.

For now, this remains a matter of some crystal ball gazing. The proposals are still at draft stage and may evolve considerably before they are enacted. However, they point towards a shift away from the current site-by-site assessment model and towards a more outcomes-based system of environmental regulation.

Conclusion

The Supreme Court has reaffirmed a clear legal principle: once planning permission is granted, the rights it confers cannot be undone by new policy or updated advice. Councils cannot revisit settled permissions unless an issue was expressly reserved or conditioned.

For developers with permissions affecting Ramsar sites, this is an important clarification. For those working within the catchments of European sites, the position remains unchanged – the Habitats Regulations continue to apply in full.

Looking ahead, the government’s proposed Planning and Infrastructure Bill could once again change the landscape, extending statutory protection to Ramsar sites and potentially reforming, or even replacing, the assessment process altogether. For now, though, CG Fry marks an important line in the sand between policy and law, offering short-term clarity in what remains an evolving area of environmental regulation.

Further information

Contact Andrew Watson