A UK court has said no to local groups trying to block a second runway at Gatwick Airport. The ruling, on 4 August 2026, removes the last major legal barrier to a £2.2 billion project that will add about 100,000 flights a year at Britain's second busiest airport. The Court of Appeal upheld an earlier decision by a High Court judge, Mr Justice Mould, who in June rejected two attempts to challenge Transport Secretary Heidi Alexander's approval of the plan (The Guardian).

Alexander approved the Gatwick scheme on 21 September 2025. The project does not involve building an entirely new runway. Instead, it moves the airport's existing emergency runway slightly and brings it into regular use for short-haul passenger planes. Gatwick expects the second runway to be operational as early as 2030 (The Guardian).

The legal challenge was brought by Peter Barclay, chair of the Gatwick Area Conservation Campaign, and a group called Communities Against Gatwick Noise Emissions. They argued that the government had not properly assessed how the expansion would affect the climate when it gave the green light. The case was heard in the High Court from 20 January 2026 and looked at both the Gatwick plan and a similar runway scheme at Heathrow. Mr Justice Mould dismissed both challenges on 23 June 2026, ruling the approvals lawful (Reuters; Judiciary UK).

Campaigners then took their case to the Court of Appeal. That court has now dismissed the challenge, confirming there are no more legal options left. Barclay said he was disappointed with the outcome (The Guardian).

The government has paired the Gatwick approval with a promise on aviation emissions. It says it is investing more than £219 million in green fuel production to cut the sector's carbon footprint. Alexander stated that the expansion would bring around 13 million more passengers and 100,000 more flights annually (The Guardian).

The Gatwick ruling comes alongside a similar legal clearance for Luton Airport's expansion. Luton Rising, the council-owned company behind Luton airport, announced that all legal challenges to its expansion plans had been cleared. The UK Supreme Court dismissed any final possibility of appealing a High Court ruling from November 2025 that upheld Alexander's approval of plans to increase Luton's annual capacity from 19 million to 32 million passengers by the mid-2040s. Luton's owner said the expansion would create up to 11,000 new jobs and generate up to an additional £1.5 billion in annual economic activity (The Guardian).

The broader context here is a ongoing tension between the UK government's push to expand airports and its legal commitments on climate change. Both the Gatwick and Luton approvals rely on a framework where the government balances aviation growth against expected improvements in sustainable aviation fuel — cleaner alternatives to regular jet fuel — and more efficient operations. The £219 million green fuel investment is the government's main financial tool for that balancing act. Whether that investment grows fast enough to offset the emissions from 100,000 additional Gatwick flights and a near-doubling of Luton's passenger numbers is a question the courts did not answer. They accepted that the government followed the right process, not that its conclusions were correct.

For the airports involved, the twin legal clearances end years of uncertainty. Gatwick's operator can now work toward a 2030 opening, and Luton's owner has a clear path to a mid-2040s buildout. The Climate Change Committee's carbon budgets — legal limits on how much greenhouse gas the UK can emit over set five-year periods — still apply outside the courts. Future policy changes, carbon taxes, or political pressure could still shift the economics of these expansions. Campaigners' failure in the courts does not remove the risk that emissions targets could force a rethink of these expansion timelines later on.