Heathrow Third Runway halted by Friends of the Earth as Court of Appeal declares Airports National Policy Statement unlawful


The Court of Appeal has declared unlawful the Airports National Policy Statement (“ANPS”), which sets out the Government’s support for a third runway at Heathrow.

The Court of Appeal allowed Friends of the Earth’s appeal against the decision of the Divisional Court (which had refused permission). It held that the ANPS was unlawful because in designating it, the Secretary of State for Transport failed to take into account the Paris Agreement on climate change, the non-CO2 climate change impacts of aviation, and the effect of emissions from the runway beyond 2050.

A National Policy Statements (“NPS”) designated under s.5 Planning Act 2008 is the vehicle for giving support in principle to a major infrastructure project. When designating an NPS, the Secretary of State has duties relating to sustainable development under s.10 of the Act, and in particular, by s.10(3), to have regard to the desirability of mitigating climate change.

When the ANPS was designated in 2018, the UK had ratified the UN Paris Agreement, which contained more ambitious global goals to limit global warming than those underpinning the UK’s legislated climate change target – at the time, an 80% reduction in greenhouse gas emissions by 2050 (s.1 Climate Change Act 2008). The ANPS assessed the climate impact of the third runway only against legislated targets, and did not consider any more stringent target that was implied by the more ambitious Paris Agreement.

Friends of the Earth argued that the duty in s.10 required an assessment that went wider than merely existing targets enshrined in legislation, and that the Secretary of State had therefore unlawfully closed his mind to consideration of the Paris Agreement. The Court of Appeal agreed, on two different bases:

  • The Secretary of State incorrectly considered that he had no discretion to consider the Paris Agreement;
  • Alternatively, even if he did appreciate that he had such a discretion, he had exercised it unlawfully: the Paris Agreement was ‘so obviously material’ to the sustainable development duties in s.10 of the Act that it was effectively a mandatory consideration.

In a related challenge by Plan B, the Court also held that, given public commitments by Ministers to uphold the objectives of the Paris Agreement, it formed part of Government policy, and so fell within the ambit of a separate duty under s.5(8) of the Act.

Friends of the Earth also argued that the ANPS was unlawful because of two further climate change issues which had not been considered:

  • Aviation has a range of non-CO2 impacts on the climate, and while some uncertainty remains about how to quantify these, the best scientific estimate is that they are as large as the CO2 impacts. Yet they were not assessed in the ANPS (and are left out of account in other greenhouse gas accounting contexts). The stark implication is that the overall impact of the runway on the climate is likely to be twice as serious as the assessed impact. 
  • The runway will operate into the 2080s (and its economic benefits were assessed on that timescale), yet the impact of CO2 emissions was only assessed until 2050. Given that the Paris Agreement contains a goal of ‘net zero’ global emissions in the second half of the century, it was relevant to consider the impact of the runway beyond 2050.

The Court of Appeal agreed that both of these factors were material and would have to be taken into account in any reconsideration of the ANPS. In relation to the non-CO2 impacts, it had no hesitation in applying the precautionary principle: that scientific uncertainty would not be used to justify inaction where the potential impacts are large.

Finally, the Court of Appeal agreed with Friends of the Earth that the Paris Agreement contained relevant environmental objectives that had to be taken into account as part of the strategic environmental assessment required under the SEA Directive.

The implications of the judgment are huge, particularly as the Secretary of State has confirmed that he will not appeal, and the court has refused permission to appeal to the Supreme Court to two interested parties (Heathrow Airport Limited and Arora Holdings Limited) who support the development:

  • The ANPS is of no legal effect unless and until the Government carries out a review under s.6 of the Planning Act 2008 that corrects the legal flaws identified by the Court. That is, if the Government wishes to continues its support for a third runway at Heathrow, it will have to go back to the drawing board and work out how the runway can be made compatible with the 100% reduction target which has now been adopted under the Climate Change Act 2008, in order to bring the UK’s domestic commitments into line with the Paris Agreement. Not only that, it will need to consider how the non-CO2 impacts of aviation, and the long-term emissions from the runway fit with the UK’s climate goals.
  • More broadly, the judgment is a ringing endorsement of the importance and relevance of climate change issues to policy making. The court was prepared to say that the enhanced goals and aspirations of the Paris Agreement were ‘so obviously material’ that no rational decision-maker could leave them out of account when considering a major infrastructure project.

The decision also contains interesting observations of the grant of relief in judicial review, and on the Mass Energy test for permission.

Peter Lockley acted for Friends of the Earth Limited (led by David Wolfe QC, with Andrew Parkinson).

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