Judicial review challenge in relation to environmental impact of Gatwick Airport expansion

A judicial review has been filed against the Secretary of State for Transport (SST) by campaign group Communities against Gatwick Noise Emissions (CAGNE) opposing plans to add a second operating runway to Gatwick Airport. CAGNE claims that the SST approved the expansion without proper assessment of its environmental impact.

Approved plan

The £2.2 billion plan for the expansion involves repurposing the current back-up runway at Gatwick Airport (the second-busiest airport in the UK), allowing it to operate alongside the main runway. It is understood that this will help the airport meet future passenger demand by serving up to 80 million passengers a year.

The planning application was accepted for detailed examination by the Planning Inspectorate on 3 August 2023 and in September 2025 it was approved by the SST to allow dual runway operations. 

Challenge

CAGNE argues:

1. the impact of the expansion on climate change has not been properly assessed and that the environmental impact assessment of the development contained gaps, including (i) a failure to properly evaluate the significance of inbound flight emissions; and (ii) a failure to assess the effect of non-carbon dioxide emissions on the climate.

2. the plans for the expansion wrongly rely on the Jet Zero Strategy (JZS). The JZS sets out the UK Government’s plan to achieve net-zero emissions for aviation by 2050, and assumes significant improvements in areas such as fuel efficiency, beyond current technology.

CAGNE has commenced the judicial review on several grounds, citing in particular the SST’s:

• flawed approach to calculating the significance of greenhouse gas emissions and/or failure to provide adequate reasons;
• error of law in the treatment of greenhouse gas emissions from international inbound flights;
• error of law in the treatment of non-carbon dioxide emissions;
• failure to take into account material risks in relation to the JZS and/or comply with the duty to make enquiries and/or irrational approach to the JZS;
• error of law in relying extensively on the JZS, which is itself unlawful;
• unlawful failure to weigh noise harms in the planning balance; and
• unlawful requirement concerning wastewater treatment.

Our thoughts

Judicial review is a powerful tool for reviewing the lawfulness of a decision or action made by a public body, and for achieving effective change to public bodies’ decision-making practices. This challenge by CAGNE illustrates how judicial review can be used by non-governmental organisations to challenge decisions made by public bodies and pursue ESG-related claims. 

The aviation sector has already been subject to actions from interest groups pursuing environmental claims in various jurisdictions, and the tool of judicial review has previously been used very effectively within the aviation sector in the UK to hold regulatory authorities to account. Most recently, various entities including environmental NGOs and the London Borough of Hillingdon have sought to use judicial review to stop Heathrow's expansion plans from getting off the ground, but, following the UK Supreme Court's decision in December 2020, these have so far proved unsuccessful.  

It remains to be seen whether this particular judicial review will achieve different results. In deciding the case, the Court will need to balance the economic benefits and industry growth goals tied up with the implementation of nationally significant infrastructure projects (such as Gatwick’s second runway) against their potentially considerable environmental impacts. 

Industry stakeholders will be watching the case carefully to see how it unfolds. In particular, the outcome may provide a useful signal to any interested parties that remain hopeful of preventing the construction of Heathrow's third runway.

Legal challenge filed against second runway at Gatwick Airport - CAGNE

Written by Christina Evered, Patrick Bettle, and Christopher Wenn.