Mr Justice Gerry McAlinden ruled at the end of June that the Department for Infrastructure had failed to show the decision was compatible with statutory climate change targets.

He acknowledged that his decision would bring “fresh anguish” to those affected by accidents on the existing A5 road and that one of the primary justifications for the construction of the new road “is that it will be much safer than the existing road”.

However, he said 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”.

Infrastructure minister Liz Kimmins earlier this week confirmed plans to appeal the ruling, and yesterday said the appeal had been lodged with the Court of Appeal.

“I am determined to see this project go ahead and therefore it is important that we appeal the decision made in the High Court on 23 June,” she said.

“Too many lives have been lost on the A5, and far too many have been injured. We owe it to those people and their families to use every opportunity available to us to improve road safety in this area.

“The A5 western transport corridor is a vital infrastructure project; my team and I have been working around the clock and will continue to do so. We are determined to build the A5.”