The applicants were brothers who owned lands in Northern Ireland. They sought judicial review of a Planning Commissioner's refusal to permit their request to develop a renewable energy wind-farm on their lands. The permit process was based on a balancing exercise weighing the wider environmental, economic and social benefits of a project against its adverse impact. The court accepted the brothers' assertion that the Commissioner's conduct of the test proceeded on a material mistake of fact. In particular, the Commissioner had failed to properly consider the environmental, economic and social benefits of the wind farm, including the importance of renewable energy generation to the UK meeting its greenhouse gas emissions targets.