Barclay and CAGNE v Secretary of State for Transport: Court of Appeal refuses permission over Gatwick expansion

The Court of Appeal has refused permission to appeal against the development consent order authorising the expansion of Gatwick Airport, dismissing challenges brought by a local resident and a community campaign group on every ground advanced.

In Peter Barclay and Communities Against Gatwick Noise Emissions v Secretary of State for Transport and Gatwick Airport Limited [2026] EWCA Civ 1040, Lord Justice Holgate and Lord Justice Dove upheld the earlier decision of Mould J in the Planning Court, which had already rejected the substantive judicial review claims following a rolled-up hearing in January.

The Secretary of State approved the development consent order in September 2025, authorising works to bring Gatwick's northern runway into routine dual-runway operation alongside associated terminal, airfield and surface access development. Mr Barclay and Communities Against Gatwick Noise Emissions, or CAGNE, separately challenged that decision, with the High Court granting permission on some grounds while dismissing the substantive claims, and refusing permission on others. Both parties sought to renew or extend their challenges before the Court of Appeal.

Mr Barclay's central argument was that the Airports National Policy Statement, which underpins the government's preference for a new runway at Heathrow, should be read as not supporting expansion at Gatwick on anything like the scale proposed, or at least as treating such expansion as a departure from policy requiring separate justification. The court rejected this comprehensively, holding that the relevant policy documents, read as a whole and in their proper context, expressly supported airports other than Heathrow making better use of existing runways, subject to environmental safeguards and a demonstrated need distinct from that met by a new Heathrow runway. The court found no arguable basis for treating Gatwick as excluded from that framework or for imposing a cap on the scale of permissible expansion.

A separate challenge, concerning whether the Secretary of State had properly grappled with disputed economic forecasts about future business passenger numbers, also failed. The court agreed with Mould J that the decision letter's conclusions on national economic benefit rested on Gatwick's distinct function as a leisure and low-cost carrier airport rather than on the contested forecasts, meaning there was no unaddressed gap in the reasoning.

CAGNE's grounds concerned the environmental assessment underpinning the consent, including the classification of greenhouse gas emissions as a moderate rather than major adverse effect, the decision not to require a quantified assessment of non-CO2 aviation emissions given continuing scientific uncertainty, and reliance on the government's Jet Zero Strategy despite evidence of delivery risk, including an internal departmental policy return not before the original decision-maker. The court found each of these to fall within the evaluative judgement properly reserved to the Secretary of State, applying a rationality standard that CAGNE could not meet, and noted that much of the underlying scientific and forecasting material remained genuinely disputed between experts in a way unsuitable for resolution on judicial review.

A final challenge to the wording of a planning requirement governing wastewater infrastructure, which CAGNE argued left room for the runway to become operational before adequate treatment capacity was secured, was also rejected as unarguable, the court finding it reasonable to assume that the relevant regulator, water company and airport operator would each act in accordance with their statutory responsibilities.

With permission refused on every ground, the development consent order stands, clearing the way for the airport's dual-runway operation to proceed.