Northern Ireland court A5 ruling clarifies scope of climate duties in infrastructure decisions

Belfast-based infrastructure experts Ciaran McNamara and Meghan Kirk of Pinsent Masons were commenting on the Court of Appeal (CoA) decision (7 pages/129 KB PDF) overturning the High Court ruling that halted the development of the delayed A5 Western Transport Corridor (A5 WTC).

The court found that the Department for Infrastructure (DfI) acted lawfully when approving the scheme, rejecting suggestions that Northern Ireland’s climate legislation creates an insurmountable barrier to major infrastructure projects.

The court held that section 52 of the Climate Change Act (Northern Ireland) 2022 requires departments to exercise their functions, so far as possible, in a manner consistent with statutory emission targets, but does not require individual projects to be accounted for within a climate action plan before they can be authorised.

The ruling reverses the July 2025 High Court decision that quashed the approval of the £1.7 billion A5 scheme after finding a gap in the evidence underpinning the department's assessment of whether the project was compatible with Northern Ireland's climate obligations.

The court noted that "there was also no suggestion that the legislation is unworkable" and said that, if such concerns genuinely arose, they should be addressed through political rather than judicial channels.

McNamara said: "The judgment will be welcomed by project developers concerned that the High Court's approach could have made it significantly harder to secure approval for major infrastructure, transport and energy developments before Northern Ireland's climate planning framework is fully implemented."

The CoA said the High Court had fundamentally erred in its interpretation of s52 of the 2022 Act. It found that the legislation does not prohibit approval of projects that increase greenhouse gas emissions, provided decision-makers have undertaken adequate inquiry and rationally concluded that approval is, so far as possible, consistent with achieving the statutory emissions targets.

According to the court, project developers are not required to demonstrate that every project’s emissions have been mapped onto a precise pathway to net zero before approval is granted. Nor is approval contingent on the existence of a climate action plan or project-specific emissions accounting exercise.

Kirk said: “The Court of Appeal has provided important clarity on how section 52 should operate in practice. The judgment confirms that climate obligations are a material and mandatory consideration for decision-makers, but that the legislation is not intended to create a project-by-project prohibition on developments that generate emissions.”

The judgment warned that imposing such requirements would exceed the obligations contained in the 2022 Act.

The court emphasised that s52 imposes a Northern Ireland-wide obligation that requires a “joined-up approach” across government departments, rather than placing sole responsibility on the decision-maker responsible for a particular project.

In this case, DfI was required to understand and assess the scheme’s emissions impact and available policy options but was not responsible for ensuring compliance across every sector of the economy.

The court found that DfI had sufficient information about the emissions associated with the scheme and had properly considered whether those emissions would undermine Northern Ireland’s ability to meet its statutory targets. It therefore rejected the High Court’s conclusion that there had been a failure of inquiry or irrationality in the department’s decision-making.

McNamara said: “For developers and public bodies, the ruling is likely to be seen as confirmation that Northern Ireland's climate legislation can operate alongside major infrastructure delivery, provided decision-makers can demonstrate they have properly considered climate impacts and their broader contribution towards meeting statutory emissions targets.”