Campaigners challenge Gatwick Airport runway plans in High Court

The climate impact of a second runway at Gatwick Airport was not properly assessed when the government approved plans, the High Court is told.

Lawyers for campaigners challenging the expansion of the West Sussex airport told the hearing the government did not assess emissions that make up “roughly two-thirds of aviation’s historical climate impacts”, and had only considered carbon dioxide.

Groups including Gatwick Area Conservation Campaign (Gacc) and Communities Against Gatwick Noise Emissions (Cagne) are fighting the plans which were approved by Transport Secretary Heidi Alexander in September 2025.

The High Court hearing, which began on Tuesday is expected to conclude on Friday.

Gatwick’s plans involve moving its emergency runway 12m (39.3 ft) to the north so that it can be brought into regular use.

The plans would cost £2.2 billion and allow about 100,000 extra flights a year, the airport said.

Estelle Dehon KC, for Cagne, argued people were “profoundly concerned” by the “impacts exacerbating climate, impacts from additional noise and impacts on waste water”.

She said the expansion would increase the number of annual passengers to 80.2 million by 2047, an increase of 13 million each year compared with if no changes were made.

She also argued the government had not properly assessed the climate impacts of the expansion and its decision was therefore unlawful.

The Department for Transport (DfT) and the airport’s owner, Gatwick Airport Limited are opposing the challenge.

James Strachan KC, for the airport, argued the assertion that there had been a failure to consider non-carbon dioxide emissions was “simply wrong”, and Gatwick Airport had assessed their impacts.

The barrister continued: “The claim is unarguable and permission [for the legal challenge] should be refused.”

The DfT will make oral legal arguments later this week.

A DfT spokesperson says: “We are backing airport expansion to deliver local and national growth, providing highly skilled jobs for local communities which will boost access to opportunity.

“We are clear expansion will only be pursued in line with our climate, noise, and environmental obligations.”

Judgement in the case being heard by Mr Justice Mould, is expected at a later date.

Additional reporting by PA Media.