Campaigners seek to appeal High Court ruling on Gatwick Airport second runway

CAGNE’s challenge concerns the Secretary of State for Transport’s decision to grant development consent for Gatwick Airport’s northern runway project, which would enable routine dual-runway operations and increase the airport’s passenger capacity to over 80 million passengers per year. 

Plans for the project were submitted in July 2023 and following an examination period, were granted development consent by the Transport Secretary in September 2025.    

In a judgment handed down on 23 June 2026, the High Court dismissed CAGNE's judicial review challenge on all grounds. In its application to the Court of Appeal, CAGNE argues that the High Court was wrong in law on the following grounds.

1. The treatment of the project’s greenhouse gas emissions: CAGNE argues that the judgment failed to resolve what it says is an irrational contradiction in the government’s decision. It argues the development was found to have a significant adverse effect on the climate and to be incompatible with the UK’s net zero trajectory under environmental assessment guidance, while simultaneously concluding that it would not materially affect the government’s ability to meet its climate targets.
2. Non-CO2 aviation emissions: CAGNE argues that both the Secretary of State and the High Court accepted these emissions were an environmental effect of the proposed development but wrongly concluded that no quantitative assessment was legally required, despite the availability of methodologies for assessing their climate impacts.
3. Reliance placed on the government’s Jet Zero Strategy: CAGNE argues that the Secretary of State failed to take account of evidence concerning delivery risks associated with the strategy or, alternatively, failed to make reasonable enquiries about those risks before relying upon it when approving the project.
4. Wastewater infrastructure: CAGNE argues that the planning requirements imposed by the government do not lawfully ensure that adequate wastewater treatment infrastructure will be operational before expansion takes place and therefore fail to address the environmental risks they were intended to prevent.

The Court of Appeal will now consider CAGNE’s application for permission to appeal.

CAGNE’s application to appeal will be heard alongside another appeal brought by local resident Peter Barclay, also contesting the decision to grant development consent.

Sally Pavey, chair of CAGNE, said:

"CAGNE, is a non-political aviation community and environment group for Sussex, Surrey and Kent. We have always looked to government and planning law for a balanced approach to aviation expansion, as suggested by aviation international policy. This judgment does not present this for local people or the planet and as such we are forced to go to appeal to reiterate our substantial concerns.

"The bill for the environmental and social costs of the Gatwick application for a new runway - similar to the Heathrow application in so many ways - should not be picked up by taxpayers, especially as the majority do not fly but will face the impacts and fallout of this new runway.   We, once again, ask taxpayers to support the appeal by donating to our legal team for the costs of appealing."

Leigh Day solicitor Julia Eriksen, who represents CAGNE, said: 

"Following careful consideration of the High Court’s judgment, our client has applied for permission to appeal because it believes there are important errors of law which should be considered by the Court of Appeal. This case raises significant issues about how the climate impacts of major infrastructure projects are assessed, the approach taken to aviation emissions, and the legal standards that apply when nationally significant infrastructure projects are approved.

"Our client remains concerned that the environmental effects of the proposed expansion have not been assessed or addressed in accordance with the law and looks forward to the Court of Appeal considering the application." 

CAGNE are crowdfunding for the costs of the appeal.