London Heathrow Airport (Heathrow Airport Ltd) is the busiest airport in Europe and has two existing runways. The Appellant (“HAL”) argued that, in order to maintain its status as the leading aviation “hub” in Europe, its capacity must increase. Therefore, R (on the application of Friends of the Earth Ltd and others) (Respondents) v Heathrow Airport Ltd (Appellant)  UKSC 52 (“R v Heathrow”) surrounded the legality of this expansion of Heathrow. The Supreme Court (“SC”) contested if the Court of Appeal was correct in determining that the government’s policy, in favour of the third runway development at Heathrow, was truly unlawful.
The policy decision under challenge was an Airports National Policy Statement (“ANPS”). The ANPS is a new runway capacity and infrastructure at airports, designated by the Secretary of State for Transport (“SoS”) under s5 of the Planning Act 2008 (“Planning Act”) in June 2018. It sets the fundamental framework within which further planning decisions will be taken. It is not planning permission – which would come later through a Development Consent Order (“DCO”), in this case – it narrows disputes at DCO stage, alike any National Policy Statement (“NPS”).
The third runway at Heathrow has been the subject of prolonged political debate, with considerable controversy as to whether its development should be supported in national policy. This controversy is further intensified by environmental concerns, and current global efforts to reduce and combat carbon emissions. However, the courts were clear that this judicial review was an entirely legal question, and not a political one.
(b) The main issues before the Supreme Court
The main issues before the SC fell within four groups:
- The statutory interpretation of section 5(8) of the Planning Act 2008;
- The application of section 10 of the Planning Act 2008;
- Reference to the Paris Agreement in the environmental report required for major developments as per the SEA Directive; and
- The consideration of emissions post-2050 and non-CO2 emissions in accordance with section 10(2) and (3) of the Planning Act 2008.
HAL succeeded on all four grounds.
(c) Court of Appeal judgment
The Court of Appeal’s judgment, in February 2020, allowed appeals by Friends of the Earth (“FoE”) and Plan B Earth, and granted declaratory relief stating that the ANPS is of no legal effect. The Court also decided that the SoS had acted unlawfully in failing to take into account the Paris Agreement in making his decision to designate the ANPS.
The Court of Appeal set out four grounds for its decision (summarised at  of the SC judgment):
- “The SoS breached his duty under section 5(8) of the PA 2008 to give an explanation of how the policy set out in the ANPS took account of Government policy, which was committed to implementing the emissions reductions targets in the Paris Agreement (“the section 5(8) ground”);
- The SoS breached his duty under section 10 of the PA 2008, when promulgating the ANPS, to have regard to the desirability of mitigating and adapting to climate change, in that he failed to have proper regard to the Paris Agreement (“the section 10 ground”);
- The SoS breached his duty under article 5 of the Strategic Environmental Assessment Directive (“the SEA Directive”, Directive 2001/42/EC of the European Parliament and of the Council on the assessment of the effects of certain plans and programmes on the environment) to issue a suitable environmental report for the purposes of public consultation on the proposed ANPS, in that he failed to refer to the Paris Agreement (“the SEA Directive ground”); and
- The SoS breached his duty under section 10 of the PA 2008, when promulgating the ANPS, in that he failed to have proper regard to (a) the desirability of mitigating climate change in the period after 2050 (“the post 2050 ground”) and (b) the desirability of mitigating climate change by restricting emissions of non-CO₂ impacts of aviation, in particular nitrous oxide (“the non-CO2 emissions ground”).”
The Court also rejected HAL’s submission based on Senior Courts Act 1981 s31, that the Court should exercise its discretion to refuse any relief, on the grounds that it was highly likely that “even if there had been no breach of duty by the SoS, the decision whether to issue the ANPS would have been the same” (para. ).
The Court of Appeal’s decision was regarded as “historic” by environmental campaigners, as it was the first ruling based on the Paris Agreement in the world. The Guardian reported that following this decision, related cases were brought against plans to build more roads and gas-fired power plants in the UK. It was a significant development in climate law, until the SC’s decision later in 2020.
(d) Arguments and Supreme Court Decision
(i) Section 5(8), Planning Act 2008:
Section 5(8) requires an explanation of an NPS to consider “government policy relating to the mitigation of, and adaptation of climate change.” The SC had to decide the correct statutory interpretation of the term ‘Government policy’.
The respondents contended that the Government’s commitment to the Paris Agreement constituted ‘Government policy’. It was therefore unlawful for the SoS, when setting out the reasons for the ANPS, to have treated the Government’s commitment to the targets in the Paris Agreement as irrelevant.
The SC disagreed with this statutory interpretation and took a purposive approach. The court considered the meaning of “government policy” within the context of the purpose of section 5(8). They found that, Parliament could not have intended to create a “bear trap” for ministers by the ordinary use of ‘Government policy’ per . The scope of what constitutes ‘government policy’ should be limited to carefully formulated written statements of policy that have been cleared by the relevant departments. In exceptional circumstances, non-written statements may also constitute ‘government policy’, but only if they can be identified as clear, unambiguous and devoid of relevant qualification, following Inland Revenue Comrs .
Accordingly, the statements of Andrea Leadsom MP and Amber Rudd MP, which the respondents relied upon and the Court of Appeal focused on, did not meet this criterion. The SC decided that it was unclear and devoid of relevant qualification as to how the commitments under the Paris Agreement could be incorporated into UK law, and so cannot be classed as ‘government policy’.
(ii) Section 10, Planning Act 2008:
Section 10 provides that the SoS, in exercising their function (in this context, promulgating the NPS), must do so with the objective of contributing towards the achievement of “sustainable development”. The definition of ‘sustainable development’ is not disputed and its objective is to meet the needs of the present, without compromising on the needs of the future.
Both the respondents and appellants did not dispute the legal approach towards this section. S10(3)(a) provides that the SoS must have regard to the desirability of mitigating, and adapting to, climate change. The SoS would be found to have acted unlawfully if material considerations were not made in contributing towards the sustainable development objective, with particular regard to s10(3)(a). Following R v Somerset CC , three categories of consideration have been established: (i) those clearly, expressly or impliedly, identified by statute as considerations; (ii) those identified in statute that must not be considered; and (iii) considerations the decision maker has discretion to take into account if it is appropriate to do so in his judgement. This final category is subject to the Wednesbury test: the considerations must have been “so obviously material” that they ought to have been considered.
The SC rejected the respondents’ arguments and reversed the Court of Appeal’s decision. The SC further subdivided the third category of considerations (above). The first sub-category is that of considerations which the SoS makes no reference to in explaining an NPS. These considerations would be subjected to the Wednesbury irrationality test. If they fail the test, then the SoS’s failure to consider a material at dispute will not be found to be unlawful. The second category are those that the SoS considers but decidedly gives no weight to at his discretion, at . The SC decided that R v Heathrow falls into the second category, in considering the Paris Agreement alongside s10. As an international treaty that is yet to be given effect in UK law, the SoS was only legally obliged to consider the UK’s commitments under it to the extent of the existing carbon target, and carbon budgets under Climate Change Act 2008 s1-4 (“Climate Act”) . On this basis, the Paris Agreement was found to have been sufficiently taken into consideration.
(iii) SEA Directive:
By virtue of the SEA Regulations, public authorities proposing major developments are required to put together an environmental report, to ensure the environmental impacts of a project are considered. An application for a DCO by HAL will also be subject to the environmental assessment through the EIA Directive and Regulations.
The respondents submitted that the SoS erred in law by deciding that the Paris Agreement was not a relevant statement of international policy, which made the environmental report produced “defective” at , . The appellants argued that the UK’s obligations under the Paris Agreement were considered – the SoS did consider the Paris Agreement, to the extent that he took into account the carbon targets under Climate Act s1.
The SC upheld the appellants arguments for this ground, as well as finding that the SoS did not treat the Paris Agreement as legally irrelevant per . The Paris Agreement was considered in accordance with Climate Change Committee’s advice, and had been sufficiently taken into account. As with the second ground, this assessment was considered lawful and there was no need to consider the Paris Agreement, beyond the extent for the environmental report.
(iv) Emissions Post-2050 and Non-CO2 Emissions:
The final ground concerned the SoS failing to consider the effect of emissions created by the NWR scheme after 2050, and the effect of non-CO2 emissions from it, per Planning Act s10(2) and (3). The respondents argued these emissions should have been considered by the SoS.
The respondents argued, with respect to the net zero carbon emission goal under the Paris Agreement, that an assessment on the impact of the emissions ought to have considered the sustainability of aviation emissions post-2050. The appellants submitted that the Airports Commission assessment did take into account that there would be carbon emissions from the NWR scheme for some years after 2050 and quantified those emissions. Given that this is the case, it was not irrational for SoS to not have considered the emissions post-2050 against policies which are yet to be determined.
Greenhouse gases – except for carbon – such as nitrogen oxides and sulphates, are non-CO2 emissions that are released from aviation, all of which contribute to global warming and greenhouse gases. It was agreed by the parties that there is scientific uncertainty as to how harmful these non-CO2 emissions are – plus where their harm falls geographically. The respondents argued the precautionary principle, and common sense, justified the quantification of these emissions despite some scientific uncertainty. The SC rejected this argument, emphasising that non-consideration of non-CO2 can be only found to be unlawful if the court can find that the SoS acted irrationally– as irrationality was the only relevant basis this was disputed . The SC added that it is not reasonable to argue irrationality for six reasons including the scientific uncertainty regarding these emissions, the consistency of the decision with the Climate Change Committee’s advice, and the fact that an application for a DCO will reconsider these environmental rules and policies.
The SC unanimously decided that the SoS’s policy on the expansion of Heathrow was lawful, construing the policy narrowly. The SC’s decision is not a surprising one and focuses on technical reasoning rather than broader environmental policy considerations, as they decided that the courts should not interfere with government policies. Professor Hilson of Reading University has commented that the judgment follows a doctrinal, conservative path, instead of an innovative climate-friendly path. Even though the signing of the Paris Agreement does not contribute to “government policy” as defined under the Planning Act, the framework of the policy statement means that the actual decision will be made in light of the environmental decisions (emissions) obligations “at the time”  of the development stage, and not in the present.
Common criticisms from environmental groups include that the increased CO2 emissions are “incompatible” with the UK’s obligations to grapple with the climate crisis. It seems that if environmental assessments were given more weighting it may have resulted in a different decision, perhaps a decision similar the Court of Appeal’s. It is well-known that aviation emissions are a significant contributor to carbon emissions and climate change. The Court of Appeal recognised this and noted that relief was needed because the third runway’s infrastructure is “one of the largest” – the effects of its development would be long-standing. The Court of Appeal also stated that current climate change commitments are a matter of “profound national importance” – demonstrated by government’s commitment to the Paris Agreement – per  and  (CA). In line with this, permitting the expansion may make it difficult to decarbonise later on. Thus, the SC’s decision means that environmental ideas and principles will be difficult to challenge past the DCO stage – the DCO stage is likely to be easier to reach because of R v Heathrow’s precedent.
Moreover, this decision is incompatible with the outcome of the Kissi-Debrah inquest. The inquest reopened an investigation into the death of Ella Adoo Kissi-Debrah under the Coroners and Justice Act 2009 and Regulations 28 and 29 of the Coroners (Investigations) Regulations 2013. The investigation concluded, for the first time, that exposure to excessive air pollution was a factor in a person’s death. The Coroners Court found that the levels of nitrogen dioxide near Kissi-Debrah’s home exceeded WHO and EU guidelines. Whilst the inquest had an entirely different function to R v Heathrow and asks different questions from those of the SC, it is nonetheless striking to have two disparate judgments surrounding climate change released on the same day – especially as both cases concern the government’s commitments to tackle air pollution.
For Heathrow, it means the third runway project can now seek planning permission to start its development, but the ultimate completion of the runway remains uncertain, as further litigation is likely to begin following the DCO stage. Heathrow’s third runway is certainly an exciting space to watch from a political, environmental and legal perspective.