Environmental Impact Assessments Must Address Consequences After Finch

Environmental Impact Assessments in the UK increasingly resemble We’re Going on a Bear Hunt. In Michael Rosen’s story, every obstacle presents the same catch phrase: “We can’t go over it. We can’t go under it. Oh no! We’ve got to go through it!” The Supreme Court’s judgment in Finch insists on the same approach. It makes clear that public authorities cannot avoid the environmental consequences of their decisions by narrowing the scope of what counts as an “effect” or by adopting technical interpretations of their obligations. They cannot “go over” or “go under” those consequences. They must go through them: legality requires a full and realistic evidential picture (see Lord Leggatt when talking about the meaning of the legislation, at paras [59][60]; causation in law, at paras [79]– [81] and the council’s approach, at paras [101]– [103]).

Yet recent developments in government policy attempt to redraw the path.  The proposed Environmental Outcomes Reports (EORs) together with recent post- Finch government guidance on environmental assessment (particularly in the offshore oil and gas context), place greater emphasis on outcomes defined by ministers and proportionate (often minimal) evidence. In doing so, they create new routes that risk bypassing inconvenient consequences. Although Finch has been treated almost exclusively as an environmental law case, it also raises a constitutional question that has, with at least one notable exception by Sonham Gordhan,  remained underexplored: who determines the evidence on which the lawfulness of administrative decisions is judged. Is it the courts or the executive?

“We can’t go over it”: Finch and the constitutionalisation of evidence

The Supreme Court in Finch held that downstream emissions from the combustion of oil extracted under a planning permission are an “indirect effect” of the project, at para 327.  Article 3 of the Environmental Impact Assessment Directive 2011/92/EU (as amended and currently transposed by the Town and Country Planning (Environmental Impact Assessment) Regulations 2017 SI 2017/571) indicates that:

“The environmental impact assessment shall identify, describe and assess in an appropriate manner, in the light of each individual case and in accordance with Articles 4 to 12, the direct and indirect effects of a project on the following factors:

(a) human beings, fauna and flora;

(b) soil, water, air, climate and the landscape;

(c) material assets and the cultural heritage;

(d) the interaction between the factors referred to in points (a), (b) and (c)“.

Rejecting the argument that only emissions from the extraction process itself were relevant, the Supreme Court emphasised that such emissions are causally connected to the project and, where their occurrence is inevitable, they must be assessed, see para [79]– [81]. This conclusion was grounded in orthodox principles. The Supreme Court stressed the need for a causal connection, see paras [112]– [118], the materiality of the effect, paras [127]– [130], and its foreseeability. It noted that it was “known with virtual certainty” that the oil would be combusted, see paras [85] and [154]. On that basis, downstream emissions could not be excluded simply because they occurred at a later stage or outside the immediate site of the project.

This is more than an environmental holding. It is a constitutional one. The Supreme Court grounded the meaning of “effects” in real-world consequences, directly confronting downstream emissions. In doing so, it constrained the executive’s ability to define away inconvenient consequences and reinforced a basic premise of public law: that legality depends on an adequate evidential basis.

It is also worth noting that this conclusion was not inevitable. Both the Divisional Court and the Court of Appeal adopted a narrower approach, treating downstream emissions as lying outside the scope of the assessment duty. The Supreme Court’s decision therefore represents a clear choice between competing conceptions of causation and relevance in public law, and a willingness to favour a more expansive, consequence-oriented approach. Seen in this light, the decision raises a deeper question about how public law understands the role of evidence in administrative decision-making. As Liz Fisher has shown, what counts as relevant information is shaped by legal practices and governance structures. Against that background, Finch can be read as extending this logic into the environmental context by constitutionalising the evidential basis of decision-making. In that sense, it treats the evidential basis of decision-making not as a matter of policy discretion, but as a requirement of legality itself.

“We can’t go under it”: EORs, government guidance and the narrowing of effects

The Environmental Outcomes Reports (EORs), introduced under Part 6 of the Levelling-up and Regeneration Act 2023, propose to replace both Environmental Impact Assessment and Strategic Environmental Assessment (EU-derived legal regimes which have structured environmental assessment in the UK for decades) with an outcomes-based system. Key features include significant ministerial discretion to define environmental outcomes, the absence of clearly defined or mandatory assessment metrics, a shift from assessing effects to demonstrating contribution to outcomes, and, in effect, a reduced emphasis on comprehensive environmental information.

Alongside this, recent government guidance, particularly in the offshore context, emphasises proportionate assessment and structured evaluation of effects (see Supplementary EIA guidance on Scope 3 emissions). While framed as clarification, this approach risks encouraging narrower evidential bases and more constrained interpretations of what counts as an “effect”. This is not merely a policy choice. It represents an attempt to reclaim interpretive control over what counts as a legally relevant consequence. In that sense, it is itself a constitutional move.

“Oh no! We’ve got to go through it”: foreseeability as a constitutional duty

At the heart of Finch is the insistence that, where environmental consequences are reasonably foreseeable and causally connected to a project, they must be assessed. This is not optional. It reflects established principles of statutory purpose, rationality, relevance, and the rule of law.

Moreover, foreseeability does more than guide interpretation. It performs constitutional work. By insisting that consequences which are “known with virtual certainty”, see para [85], must be assessed, the Court anchors legality in the real world, making it clear that legality cannot be redesigned by administrative architecture therefore limiting the ability of the executive to curate the evidential landscape. Seen in this light, foreseeability operates as a constitutional constraint. It prevents administrative frameworks from redefining legality by narrowing what counts as an effect. It is worth noting that Lord Sales, dissenting, offers a more institutionally constrained account, treating the scope of relevant effects as a matter for evaluative judgment within the planning framework (see paras [200]– [210]).

Why this matters for constitutional law

Finch can be read as exposing a potential tension within UK public law, particularly in the climate change and environmental assessment context. In this area, the courts have shown a heightened attentiveness to evidential completeness, suggesting that legality may require decision-makers to confront the full consequences of their actions. By contrast, the executive has, in certain regulatory frameworks, adopted more circumscribed evidential approaches, through which legality is shaped by what decision-makers are formally required to consider. This tension may, however, be contingent on the statutory context and should not be overstated as a general feature of public law beyond the climate sphere.

This tension raises fundamental constitutional questions about who defines the scope of legally relevant consequences and whether the executive can reshape evidential duties through legislation and guidance. It also invites scrutiny as to what happens when judicial doctrine and administrative design diverge.  Underlying all of this is a deeper question about whether the rule of law requires a sufficiently complete evidential foundation for administrative decision-making. Finch suggests that legality cannot be starved of evidence. By contrast, recent reforms suggest a competing vision in which evidential obligations are more tightly controlled by the executive. This is why Finch should be read not only as an environmental case, but as a constitutional one, as it raises some core questions about the separation of powers.

Post‑Finch case law: the courts keep going through it

Subsequent and related case law suggests a judiciary increasingly unwilling to accept weak evidential foundations when it comes to climate‑related decision‑making. Post‑Finch, the High Court in Friends of the Earth v Secretary of State for Energy Security and Net Zero [2024] EWHC 995 (Admin) held that the Secretary of State lacked the information necessary to rationally conclude that statutory carbon budgets would be met, confirming that unclear or incomplete evidence cannot satisfy legality. This approach builds on earlier cases such as Friends of the Earth v Secretary of State for BEIS (No.1) [2022] EWHC 1841 (Admin), where the courts found that ministers had approved the Net Zero Strategy without the quantified analysis required to understand whether carbon budgets would in fact be delivered. Although these cases arise under different statutory regimes, they share a common judicial insistence that legality cannot rest on incomplete or speculative evidence.

However, this trajectory is not uniform. In R (Friends of the Earth Ltd, Jordan and Paulley) v Secretary of State for Environment, Food and Rural Affairs [2024] EWHC 2707 (Admin), concerning the National Adaptation Programme, the Court adopted a more deferential approach, accepting a comparatively limited evidential basis within the statutory framework and emphasising the breadth of executive discretion.

Taken together, these decisions, which culminated in the Supreme Court’s insistence in Finch ** that decision‑makers must confront real‑world environmental consequences, demonstrate an emerging, but not uniform, judicial trend towards demanding evidential rigour, analytical transparency, and substantive engagement with climate reality. Nor is this development necessarily confined to environmental law.

The insistence on an adequate evidential basis for administrative decision-making has been increasingly visible across public law more generally, particularly in cases concerning rationality and statutory purpose, such as R (Evans) v Attorney General [2015] UKSC 21 , at paras [52] – [53] and R (UNISON) v Lord Chancellor [2017] UKSC 51, at paras [90] – [98] where the courts emphasised that executive decisions must be properly justified and grounded in their real-world effects. What Finch does is crystallise and intensify that tendency in a context where the consequences are spread widely and unfold over time. In that sense, it may be less of a new development and more a clear example of an existing trend in the law.

Conclusion: the rule of law and the path ahead

We’re Going on a Bear Hunt ends with the characters realising that some obstacles cannot be avoided. They must be faced directly. So too with environmental consequences. ** Finch insists that legality requires going through the evidence. Emerging reforms risk creating new paths around it. The coming years will determine whether the courts’ commitment to real world consequences of administrative action prevails, or whether administrative design will allow the executive to narrow legality by redefining what counts as an effect.

Whether this shift toward greater judicial control is desirable is ultimately a matter of constitutional perspective. On the one hand, requiring decision-makers to confront the full consequences of their actions strengthens the rule of law by preventing legality from being shaped by administrative convenience. On the other, it risks drawing the courts into policy decisions and value judgments traditionally reserved for the executive, particularly in technically complex fields such as climate governance. Finch sits at the centre of this tension: it enhances legal accountability, but in doing so,  pushes the boundaries of judicial oversight. At stake is not simply environmental law, but the constitutional balance between courts and the executive in defining the conditions of lawful decision-making.

Many thanks to David Stott, Nina Pindham and Dr Trueblood for their comments on a previous version of this blog. Any errors remain my own.

Antoinette Nestor is an academic lawyer at the University of Cambridge. Her research focuses on public law, environmental law and climate governance, with particular interest in how public authorities justify decisions and account for their real-world consequences in environmental and planning contexts. She also serves as a Cambridge City Councillor.

(Suggested citation: A. Nestor, ‘“We’re Going on a Bear Hunt”: Real-World Consequences and Environmental Assessment after Finch ’, U.K. Const. L. Blog (22nd April 2026) (available at https://ukconstitutionallaw.org/)))

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