In February 2020, the Court of Appeal decided that the Government policy on airport expansion at Heathrow was unlawful on climate change grounds. The Supreme Court has now reversed this decision. David Hart QC considers this development.
R (o.t.a Friends of the Earth et al) v. Heathrow Airport Ltd  UKSC 52 – read judgment
The policy decision under challenge was an Airports National Policy Statement (ANPS). An NPS sets the fundamental framework within which further planning decisions will be taken. So, in traditional terms, it is not a planning permission; that would come later, via, in this case, the mechanism of a Development Consent Order (DCO), which examines the precise scheme that is proposed. The ANPS (like any NPS) narrows the debate at the DCO stage. Objectors cannot say, for example, that the increase in capacity could better be achieved at Gatwick. Government policy has already decided it shouldn’t be.
The ANPS was made in 2018 by the Secretary of State for Transport (Chris Grayling), after many years of commissions and debates about airport expansion.
The other major policy player in this litigation was the Paris Agreement on Climate Change. This was concluded in December 2015, and was ratified by the UK on 17 November 2016. The Paris Agreement commits parties to restrict temperature rise to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels.
The UK’s domestic climate change legislation derives from the Climate Change Act 2008. The Planning Act 2008 (setting out the NPS system) required government in a given NPS (a) to explain how it takes account of its policy on climate change (s.5(8)) and (b) to exercise its NPS functions with regard to the desirability of mitigating and adapting to climate change (s.10).
The challenges debated in the Supreme Court revolved around (1) these two sections of the PA 2008, (2) a debate about the impact of the Strategic Environmental Assessment Directive (2011/92/EU), and (3) claims that the SoS has failed to take into account long-term (post-2050) and non-CO2 emissions.
One curious element of this appeal is that it was Hamlet without the Prince. After seeking to defend the case in the CA, the SoS did not appear in the SC, where Heathrow did all the running. Whether this non-appearance by the SoS was anything to do with the Honourable Member for Hillingdon’s undertaking (Boris Johnson MP) some years ago to lie in front of the bulldozers before the third runway was laid is of course unknowable. But as we shall see, this did not stop Heathrow’s arguments winning the day. So, possibly, central government’s policy objective achieved without political risk.
Section 5 PA 2008
It was argued that it was unlawful for the Secretary of State when setting out his policy in the ANPS to treat as irrelevant the Government’s commitment to the temperature target in the Paris Agreement and the introduction of a new net zero target. The Government’s commitment constituted “Government policy” within the meaning of s.5(8) PA 2008.
The challengers pointed to statements by Ministers in the House of Commons that the Government would enshrine the net zero targets in UK law in due course.
The CA had decided that these statements were “policy” within s.5(8).
The Supreme Court disagreed. s.5(8) concerned “carefully formulated written statements of policy” such as those found in an NPS or the National Planning Policy Framework. It reasoned thus at 
For the subsection to operate sensibly the phrase needs to be given a relatively narrow meaning so that the relevant policies can readily be identified. Otherwise, civil servants would have to trawl through Hansard and press statements to see if anything had been said by a minister which might be characterised as “policy”. Parliament cannot have intended to create a bear trap for ministers by requiring them to take into account any ministerial statement which could as a matter of ordinary language be described as a statement of policy relating to the relevant field.
The Court drew on the law of legitimate expectation setting an “absolute minimum” required for a policy to qualify under s.5(8). It must be clear, unambiguous and devoid of relevant qualification. The Court considered that the ministerial statements did not satisfy those criteria. The statements did not refer to the temperature targets at all, and left open the question as to how net zero was to be enshrined in UK law. This was “inchoate or developing policy being worked on within Government” .
All agreed in the Supreme Court that the UK’s ratification of the Paris Agreement did not amount by itself as “Government policy”. This was an act on the international plane and gave rise to no legal rights or obligations in domestic law: . So far so good, but the requirement under s.5(8) is not not for law but for policy. Policy by definition is not law, nor does it generally give rise to legal rights and obligations without it being implemented – just like international law. This was a point which was in effect made by the CA at  in saying that concentration on the legal effect was a “distraction” from the s.5(8) question. But the point was not taken further in the SC.
The Court dismissed one element of Heathrow’s argument. The Climate Change Act 2008 (CCA) contained a statutory mechanism by which targets could only be changed with the assent of Parliament. Heathrow said that this statutory mechanism had the effect that there was no remaining prerogative power to adopt different policies without the assent of Parliament – a principle laid down in cases like Fire Brigades Union.
The Court disagreed. Policy for this purpose was not necessary the same as a policy falling within s.5(8). For example, Government could record in an NPS that it intended to modify a specified carbon target via draft subordinate legislation dependent on Parliamentary asset – and that would be policy even though not yet formalised.
But, on the facts, the Supreme Court said, there was no settled policy on how the Government would adapt its domestic policies to contribute to the global goals of the Paris Agreement. By the time of the ANPS in June 2018, the Climate Change Committee (CCC) had not yet stated what the new carbon target should be, and was advising Government to await the forthcoming IPCC Special Report on Global Warming (which was in the event published in October 2018). It was not until May 2019 that the CCC recommended that a new statutory target should be set at net zero.
Section 10 PA
Section 10 PA requires the SoS to act with the objective of contributing to sustainable development. “Sustainable development” is (my words) a weasel phrase, which in this case involves the balancing of economic developments against increased greenhouse gases. Sounds cuddly but means nothing if you really want to do some major infrastructure project because you, if so inclined, can always say that the money busts climate change or other environmental issues. But this question depends on how this particular obligation is to be interpreted in its statutory context, and the principle is capable of more edge in other contexts.
S.10(3)(a) PA requires the SoS to have regard to the desirability of “mitigating, and adapting to, climate change.”
- of the judgment are an economical summary of the law on relevant/irrelevant considerations in a statutory context such as s.10 PA. The starting point is the seminal case of Fewings. There are three categories; (1) considerations expressly or impliedly identified in the statute; (2) considerations excluded by the statute; and (3) considerations to which the decision-maker may have regard in his discretion. Category 3 is always the debatable one.
The Court divided Category 3 cases into those (a) where the decision-maker did not refer to a particular consideration at all  and (b) where the decision-maker decided to give a consideration identified by them no (or no substantial) weight in their ultimate analysis.
The Court said this case was a Category 3(b) case. Disagreeing with the CA, it said that the SoS took into account his duties under the CCA (and hence, it was said, the Paris Agreement). He, it was said, gave weight to that Agreement and, to the extent that its obligations were covered by measures taken under the CCA, ensured that those obligations would be brought into account when decisions were taken pursuant to the framework set by the ANPS – i.e. in the DCO process.
Hence, the Court identified the remaining question to be whether the SoS acted irrationally in omitting to take the Paris Agreement further into account.
Astute readers will have guessed that, once the question was formulated in this narrow way, there was only one likely answer. No irrationality.
On the evidence, the Secretary of State certainly did ask himself the question whether he should take into account the Paris Agreement beyond the extent to which it was already reflected in the obligations under the CCA 2008 and concluded in the exercise of his discretion that it would not be appropriate to do so.
So end of challenge on this ground.
The SEA point
The Strategic Environmental Assessment Directive (transposed effectively into domestic regulations) is designed to ensure that environmental impacts from major developments are taken into account. It operates “upstream”, when major plans or proposals are being prepared. “Downstream” comes the Environmental Impact Assessment process, when the specific decision is to be made.
Let’s go back to Paris – if we can, these days. The complaint was that the SEA report prepared made no reference to the Paris Agreement. The response was that the Appraisal of Sustainability (abbreviated to AoS in this part of the judgment – public lawyers beware) which underpinned the ANPS and the draft ANPS itself referred to the carbon targets in the CCA, and hence the Paris Agreement was ‘to that extent” covered in the SEA report. The SoS was following the advice of the CCC that it was not “necessary or appropriate” to make further reference to the Paris Agreement, even though it was an implicit reference in the the draft ANPS. The Court thus rejected the conclusion of the CA that it was legal advice which led to the deletion of the reference to the Paris Agreement.
Whatever you think of the outcome, it is deeply odd that a major policy document on airports can be finalised in 2018 without explicit reference to the Paris Agreement concluded some 3 years before. It is as if it is the unmentionable.
ff consider the effect of the SEA. An SEA report has to provide environmental information in terms of international, EU or domestic objectives – but the SoS has a discretion as to the information to be included in the report. This discretion was only reviewable on Wednesbury grounds: . This claim was not made out: [149}
…. the Secretary of State did not treat the Paris Agreement as legally irrelevant and on that basis refuse to consider whether reference should be made to it. On the contrary, ….. in compiling the AoS as the environmental statement required under the SEA Directive the Secretary of State decided to follow the advice of the CCC to the effect that the UK’s obligations under the Paris Agreement were sufficiently taken into account in the UK’s domestic obligations under the CCA 2008, which were referred to in the ANPS and the AoS.
Post-2050 and non-CO2 emissions
These grounds were found good by the CA but were reversed by the SC. The SC accepted that the SoS had not acted irrationally in not taking into account post-2050 emissions, given the difficulty of assessing these.
Similarly, aircraft emit nitrogen oxides, water vapour, and sulphate and soot aerosols all of which combine to have a global warming effect over and above the effect of carbon.
The uncertainty lies in the quantification of this effect. Heathrow pointed to the fact that the AoS specifically invited Heathrow when applying for a DCO to do further work on assessing these impacts – so not a matter for the ANPS.
The CA, unsurprisingly, invoked the precautionary principle (and common sense) in ruling that you would not refuse to take something into account because you could not currently quantify it.
The SC dismissed this argument at , in a somewhat cursory fashion, saying that the CA was equating the precautionary principle with common sense. Environmental lawyers will know that the precautionary principle has rather more backbone than this gives credit for.
The CA decision was reached in February 2020. How different a flight world was that? The obvious question about this is why is Heathrow bothering to appeal. The pandemic has destroyed the current market for air travel. But Heathrow’s view  is that, given the long lead time for any third runway, the surplus of demand over current capacity will arise before a third runway would be operational, and that it will proceed with the scheme. A very substantial company wanting to preserve its corporate value, would say that, wouldn’t they.
But that issue should not distract from the important legal and policy questions which arise on the central point in the case. Essentially, the difference between the CA and the SC turned on their assessment of the rather opaque documents which underlay the ANPS. The CA smelt a rat: it was all driven by a mistaken view of the SoS’s legal obligations in respect to Paris: mustn’t mention it. The SC read things differently: even though Paris was not mentioned in the ANPS, it lurked there. So it was taken into account, really. On these different perceptions hinged this very important infrastructure challenge.