The Scrutiny of Scientific Evidence by UK Courts in Environmental Decisions: Legality, the Fact Law Distinction, and (sometimes) Self-Limiting Review, by C Caine and R Broadbent

In the UK, claims regarding the Habitats Directive are dealt with through two main avenues: judicial review/statutory appeal, and the Tribunal system. In judicial review and statutory appeal cases, only the legality rather than the merits of decisions can be assessed, as the courts are unwilling to assess the substance of decisions or to re-make the decisions of a public body. The court’s justification for this is that doing so would infringe upon the separation of powers. Despite this justification, environmental decision-making lacks a substantive, merits-based examination by the court. However, this is not the only option for environmental decision-making relating to the Habitats Directive. For example, the Tribunal system, which considers appeals against enforcement action in the form of environmental civil sanctions, is able to take the scrutiny of environmental decision-making beyond an assessment of legality.

Background: Avenues for Environmental redress in the UK

The main route for challenging decisions made with respect to the Habitats Directive in the UK is through judicial review or by statutory appeal to a planning permission decision. In addition to this, in respect of the relatively new arena of civil sanctions, a tribunal system has been introduced under the Regulatory Enforcement and Sanctions Act 2008 (RESA 2008). The level of scrutiny that each of these systems is able to afford to scientific evidence in environmental cases differs somewhat, as outlined below. Cases under judicial review and statutory appeal can only be brought under three grounds: illegality (did the decision-maker act within law that regulates their decision-making power?), procedural impropriety (has the decision infringed either ‘the rule against bias’ or ‘the right to be heard’?) or irrationality (also known as Wednesbury unreasonableness – is the decision ‘so outrageous in its defiance of logic or accepted moral standards that no sensible person who had applied his mind to the question to be decided could have arrived at it’?). Cases which are brought under RESA 2008 can be on the basis that in issuing the civil sanction, there was an error of law or fact, or it was unfair or unreasonable for any reason. An appeal is heard in the First-tier Tribunal, with the option of appealing against the First-tier Tribunal in the Upper Tribunal. However, appeals to the Upper Tribunal are on points of law only – so for example if the First-tier Tribunal did not apply the law correctly, did not follow the correct procedures, did not have enough or any evidence to support its decision, or did not give adequate reasons for its decision.

The Limitations of Decision-making in Judicial Review and Statutory Appeal: Assessing the Legality of Decisions instead of the Merits

As outlined above, the judicial review and statutory appeal processes in the UK are restricted by three grounds under which a case can be brought – these grounds all relate back to legality. In Plan B Earth v Secretary of State for Transport [2019] EWHC 1070 Admin); [2020] EWCA Civ 214, the Court confirmed that Wednesbury irrationality was the appropriate test to be used, with the Court of Appeal judgment in the case stating that ‘the Court’s reviewing role does not stretch to determining disputed issues of technical expert evidence’. The standard of review and balance of decision-making authority was also discussed in Smyth v Secretary of State for Local Community and Government [2015] EWCA Civ 174. Even in instances where a judge appears to personally find the justification for a decision to be unconvincing, they will not intervene as long as they are satisfied that the decision-maker has acted rationally in accordance with Wednesbury irrationality. This was the case in RSPB v The Secretary of State for Environment Food and Rural Affairs & Ors [2015] EWCA Civ 227 where the Court stated that ‘if this was an appeal on the merits I would have said that they are unconvincing, but I am unable to conclude that they are irrational’. Most recently, the unchanged position of the Court has been confirmed in R (Wyatt) v Fareham Borough Council [2021] EWHC 1434 (Admin) where Sir Keith Lindblom stated that ‘experts may be expected to provide enough explanation to enable the court to decide whether the views they have stated are based on a conspicuous error… But the court will bear in mind that decisions which entail “scientific, technical and predictive assessments by those with appropriate expertise” and which are “highly dependent upon the assessment of a wide variety of complex technical matters by those who are expert in such matters and/or who are assigned to the task of assessment (ultimately by Parliament)” should be accorded a substantial margin of appreciation’.

When the court does intervene on grounds of irrationality, it will only do so when the decision, appears to be inexplicable. For example, in the case of Wealden DCI v Secretary of State for Communities and Local Government & Ors [2017] EWHC 351 (Admin), where the decision-maker had concluded that increased traffic arising from planned development would not have a significant impact on the site as long as the traffic increase was less than 1,000 cars per day. However, the increase in housing provision in the plan ultimately took the traffic increase to a level that exceeded 1,000 cars per day. Despite this, Natural England drew the same conclusion that the damage would not be significant, directly contrasting their previous statement. Whilst reluctant to do so, the Judge ultimately concluded that the decision taken in this case was not rational, as the decision-maker had effectively contradicted themselves.

An Alternative Approach in the Tribunal System under RESA 2008

In contrast to the Court’s approach in judicial review and statutory appeal, the Tribunal system appears to show more of a willingness to scrutinise environmental decision making. This is suggested by Justice McKenna’s assertion in Warren v Natural England [2018] UKFTT NV_2018_0006 (GRC): ‘the appeal is de novo i.e. it requires the Tribunal to stand in the shoes of the regulator and take a fresh decision on the evidence, giving appropriate weight to the original decision-maker’s decision’. The case concerned the appeal of a stop notice preventing the release of gamebirds. The First-tier tribunal used its de novo powers to substantially vary the stop notice. Whilst doing so, it questioned the status and expertise of Natural England’s ‘unsatisfactory’ witnesses and gave their evidence less weight than the Appellant’s witnesses. This was then successfully appealed to the Upper Tribunal (Natural England v Warren [2019] UKUT 300 (AAC)) where the First-tier Tribunal’s approach was scrutinised. Here, it was stated that because the Tribunal “stood in the shoes” of Natural England, it was ‘… bound to apply the principles that governed Natural England’s decisions… these included giving effect to the Habitats and Birds Directive (and therefore to the precautionary principle) in exercise its function in serving the stop notice.’

Does the UK’s Approach Conform with International Requirements as well as its own Constitutional Norms?

Clearly in the UK the Courts in judicial review and statutory appeal regard that their rightful role is far less “hands on” than the Tribunal. In 2016, Lees noted that the way in which the courts in the UK are limited to the role of ‘overseer, rather than allowing for a full merits review’ contrasts with the approach taken by the CJEU where the robustness of scientific evidence is expressed as a matter of legality, rather than as a question of discretionary judgment. This contrasting approach was noted by Mr Justice Jay in the High Court in 2021 where the issue of deeper scrutiny was sidestepped in the following remark ‘it is true, as we have seen… the judgment of the CJEU in the Dutch Nitrogen case refers to obligations of the national courts to undertake a thorough and in-depth scientific assessment, and that a distinction is made between these and the competent authorities… it is to be recalled that administrative courts throughout the EU do not apply a uniform standard to what we (and in many cases, they) call judicial review.’

The UK has also been subject to compliance challenges before the Aarhus Convention Compliance Committee (ACCC) which assert that the UK’s strict judicial review criteria mean that it is in breach of Articles 9(2), 9(3) and 9(4) of the Convention. In 2008, the ACCC found that the UK was compliant with the Convention’s requirements, however noted that the Wednesbury test provided for a ‘very high threshold for review’. Another challenge was raised again in 2017 where the UK continued to argue that the complainants failed to provide any evidence or overview to suggest that access to justice would be improved if the process of judicial review were to be changed so as to incorporate a different standard of review. The Committee’s findings on this have not yet been released as they were delayed by Covid-19.

Whilst there are those who argue that judicial review and statutory appeal should be widened in order to allow for judges to scrutinise the merits of environmental decisions, we contend that the current level of scrutiny is compliant with constitutional norms in the UK, namely the separation of powers. Any proposed change to the current judicial review and statutory appeal processes would require a constitutional overhaul in order to allow for merits-based decision-making. The benefits of such an overhaul could lead to greater accountability of decision-makers, but would come at the cost of diluting the separation of powers and possibly requiring judges, who do not possess the relevant scientific expertise, to pass judgment on complicated scientific matters. Even if calls for a specialised environmental court were answered and the UK introduced environmental courts with specialist judges, there is much more to environmental decision-making than simply deciding on scientific uncertainty alone. While the court is often viewed as a neutral and objective arbiter of scientifically uncertain environmental law cases, perhaps what is needed is a reinvestment in our politics, rather than an overhaul of the Court system.

Posted by C Caine and R Broadbent

Catherine Caine is a Senior Lecturer in Law at the University of Exeter with research interests in environmental law, planning law, and energy law. Catherine’s research projects include an analysis of whether the European legal requirements of habitat protection have been integrated and coordinated into the planning and construction processes for offshore renewable energy, a comprehensive review of the extent to which the courts in the UK consider scientific evidence in Habitats Directive decisions, and an analysis of the regulation of heat networks in the UK. Catherine has also recently been the PI of an interdisciplinary research group analysing the way in which taxation and labelling on unhealthy and unsustainable food would change consumer behaviour in the UK.

Richard Broadbent was a solicitor at Natural England since 2010 and was the Head of Legal Services since 2017. Richard led on many of Natural England’s high-profile litigation and enforcement cases and advised on policy developments such as the emergence of the Environment Act 2021 and Nature Recovery Green Paper. Richard is a highly distinguished environmental lawyer and has worked on a number of high-profile nationally significant infrastructure, planning, and species licencing cases. These include nuclear power stations, offshore windfarms, port developments and HS2. Richard trained at Collyer Bristow LLP in London and holds an LLM in Environmental Law from UCL.

The content of this post has been derived from the chapter: ‘The Scrutiny of Scientific Evidence by UK Courts in Environmental Decisions: Legality, the Fact-Law Distinction, and (sometimes) Self-Limiting Review’ by Catherine Caine and Richard Broadbent, which is published in the upcoming book, Environmental Principles and Scientific Uncertainty before National Courts – The Case of the Habitats Directive co-edited by Mariolina Eliantonio, Emma Lees, and Tiina Paloniitty.

Suggested citation: C Caine and R Broadbent, “The Scrutiny of Scientific Evidence by UK Courts in Environmental Decisions: Legality, the Fact Law Distinction, and (sometimes) Self-Limiting Review” available at