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The UK’s Secretary of State for Transport introduced a national policy in June 2018 entitled the “Airports National Policy Statement: new runway capacity and infrastructure at airports in the south east of England” (ANPS). The ANPS provided for the provision of a Third runway at Heathrow airport. This was vigorously opposed by local authorities and residents groups in the vicinity of Heathrow, the Mayor of London and various non-governmental environmental organisations. The objecting groups issued a number of different Judicial Review applications which were ultimately rejected by the Divisional Courts.

One ground to rule them all

The Court of Appeal upheld the various rulings of the Divisional Courts dismissing those challenges, save on one ground. This ground was that in approving the ANPS, the Secretary of State had failed to take account of the Paris Agreement on the United Nations Framework Convention on Climate Change (the Paris Agreement).

Section 5(8) of the Planning Act 2008 obliges the Secretary of State to set out in a national policy statement such as the ANPS, how that policy statement takes account of ‘Government Policy’ regarding the mitigation of, and adaptation to, climate change.

The Secretary of State had argued that the Paris Agreement did not represent ‘Government Policy’ as it was not incorporated into domestic law. In addition, the Secretary argued that at the relevant time the government’s statutory advisor on climate change, the Climate Change Committee (CCC) had not expressed a view on how the Paris Agreement could be given effect to in the UK. Accordingly, the Secretary of State had argued that there was no obligation to have regard to the Paris Agreement in formulating the ANPS, and further argued that in fact there was no entitlement to do so.


The Court of Appeal found that in fact the Paris Agreement was “clearly part of Government policy” by the time that ANPS was designated. This was due to the fact that the Paris Agreement was formally ratified by the United Kingdom on 18 November 2016. Furthermore, there were firm statements by Ministers re-iterating UK Government policy of adhering to the Paris Agreement.

The Court of Appeal therefore found that the Secretary of State had failed to comply with Section 5(8) of the 2008 Act as there had been no consideration at all of an element of Government policy relating to climate change namely the Paris Agreement, which had been ratified by Parliament. As the Court stated:

requiring the Crown to comply with what has been enacted by Parliament (in this case the obligations in section 5(8) of the Planning Act) is an entirely conventional exercise in public law.

The Court pointed out that the obligation on the Secretary of State was not necessarily to adopt policy consistent with the Paris Agreement, but to ensure that he complied with the will of Parliament by having regard to that Agreement. The Court went on to hold:

If the Secretary of State was to comply with his duty under section 5(8) of the Planning Act, the implications of the Paris Agreement for his decision, and whether they were different from the implications of meeting the targets under the Climate Change Act, were matters for him specifically to consider and explicitly address in that very exercise. But he did not do so. It is clear that, in deciding to designate the ANPS, he did not take the Paris Agreement into account at all. On the contrary, as we understand it, he consciously chose – on advice – not to take it into account. And in our view, as we have said, his failure to take it into account was enough to vitiate the designation.

In addition, the Court found that the Secretary of State failed to comply with the Strategic Environmental Assessment (SEA) Directive, as the SEA carried out, as required under the Directive in respect of the approval of the ANPS did not include reference to the Paris Agreement.

The Court ruled that this represented an error of law in that Annex I to the SEA Directive requires the consideration of “the environmental protection objectives, established at international…level which are relevant to the plan or programme and the way those objectives and any environmental considerations have been taken into account during its preparation.”

The failure to consider the Paris Agreement therefore rendered the SEA and thereby the ANPS itself unlawful.

The Court therefore proposed to make an Order quashing the designation of ANPS, which would allow the UK government to reconsider the ANPS, and thereby the proposal for the third runway at Heathrow, in light of the requirements of the Paris Agreement.

Potential implications in Ireland

It is clear that the decision may be of some significance for major infrastructure projects in Ireland. Ireland also ratified the Paris Agreement in November 2016. Ireland also has a dualist legal system requiring an international treaty such as the Paris Agreement to be implemented into domestic law through a national statute before it could have effect at the domestic level. In addition, Ireland is subject to the SEA Directive and going forward it will be important that all plans and programmes in relation to major infrastructure projects subject to the SEA Directive consider the requirements of the UNFCCC and the Paris Agreement.

It is noteworthy than in a number of recent decisions that An Bord Pleanála (ABP) inspectors have referred to the Paris Agreement. In the recent West Offaly Power decision, the ABP Inspector considered the requirements of the Paris Agreement in recommending the refusal of the permission.

Under Section 143 of the Planning and Development Act 2000 (as amended), ABP is required when performing its functions to have regard to “the policies and objectives for the time being of the Government”. If the Court of Appeal decision was to be applied here, it would follow that the Paris Agreement is something to which ABP must have regard when determining planning applications before them. What this might mean in practice would remain to be seen, and whether ABP would be required to consider the impacts of particular projects on achieving Irelands Nationally Determined Contributions (NDCs) under the Paris Agreement, which form part of the Paris Agreement’s objective of maintaining overall global temperature rise to no more than 1.5° above 1990 levels.


What is clear from the decision of the UK Court of Appeal in relation to the third Heathrow runway is that international climate objectives can have major consequences for the development of infrastructure with long-term climate impacts, with the Courts not being reluctant to strike down very significant projects. We will continue to monitor the impact of this decision and its potential implications for planning and environmental law in Ireland.

For more information on how this decision could potentially affect projects in Ireland, contact a member of our Planning & Environment team.

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