The Department for Infrastructure is appealing against a High Court ruling from June which quashed a decision to proceed with the first phase of the project because the Department had failed to show it was compatible with statutory climate change targets.

Mr Justice Gerry McAlinden said in his ruling that the “principle of the rule of law cannot be subverted, even if the motivation for doing so is to achieve what is deemed to constitute a clear societal benefit”.

DAERA is now seeking to intervene in the judicial review in support of the Department for Infrastructure.

Infrastructure minister Liz Kimmins said: “The A5 is a hugely significant infrastructure project not least because of the road safety improvements it will bring and the lives that will be saved as a result.

“Last month we submitted a robust appeal to the court against the decision made in the High Court on 23 June.  

“I welcome the comments made by my Executive colleague, [DAERA] minister Andrew Muir, that his department intends to apply to the court to formally intervene in the A5 appeal.

“My officials and legal team are working around the clock on this to submit a robust and comprehensive appeal.

“I am determined that this road will be built, and it is important that everyone who wants to see this happen works together in a constructive way to achieve that goal.”

Andrew Muir, DAERA minister, added: “Throughout my time as DAERA minister, I have been clear about the importance that I place on climate action. The journey to net zero is the defining challenge of our generation.

“The Climate Change Act (Northern Ireland) 2022 was a central feature of the judgment made in the High Court on 23 June 2025.

“I have decided that it is appropriate for my Department to apply to the court to formally intervene in the appeal.

“The focus will be on clarifying the interpretation of the legislation so that it can be fully implemented as intended.”