Heathrow Airport, the UK's busiest airport, which serves over 80 million travelers annually, has indicated that its planned third runway may face a delay of up to four years due to planning and regulatory challenges. The government initially aimed for the new runway, projected to cost £33 billion, to be operational by 2035. However, Heathrow has expressed concerns about meeting this timeline without further simplification of the planning process. The airport hopes to secure planning permission by 2029 and subsequently open the runway within a decade.
The Department for Transport (DfT) acknowledged that the project's timeline has always been ambitious and stated it would continue to collaborate with stakeholders to advance the matter. Heathrow's core scenario has been to open the new runway within ten years of obtaining planning permission. The airport noted it is encouraged by the Chancellor's initiatives to streamline infrastructure and eliminate regulatory bottlenecks, committing to work with ministers, airlines, and stakeholders to expedite the planning application.
Former Chancellor Rachel Reeves announced government support for the project in January 2025, citing economic growth as a key benefit. Prime Minister Andy Burnham, who had previously expressed criticism, stated he is now open-minded about the expansion. Despite facing significant opposition from environmental activists and local residents, the project is projected to create approximately 100,000 jobs and contribute to a broader £49 billion modernization of the airport.
The expansion would necessitate the demolition of numerous homes, the diversion of rivers, and the rerouting of the M25 motorway through a tunnel beneath the new runway. The number of flights from Heathrow, currently limited to 480,000 annually, could increase to 720,000, averaging nearly 2,000 flights per day.
London Mayor Sadiq Khan has consistently opposed the new runway, citing concerns over noise, air pollution, and climate change. The government's climate advisers recently stated that the expansion should proceed only if airlines are mandated to invest in cleaner flying, which could increase flight costs. Transport Secretary Heidi Alexander noted that while the advisers presented one perspective, there are multiple pathways to fulfill climate change obligations.
A draft planning framework for the expansion was published in June for consultation. Once finalized, it will require parliamentary approval, which could be postponed until 2027. A DfT spokesperson confirmed that there is currently no active planning application for the third runway and refrained from commenting on ongoing consultations that could hinder progress. The spokesperson emphasized the ambitious nature of the timeline and the commitment to work with Heathrow and other stakeholders to establish the necessary framework for a planning application.
A Heathrow spokesperson stated that ambitious targets are essential and that the sooner expansion begins, the sooner the UK will benefit. They highlighted that the project is expected to generate at least 108,000 new jobs and billions in supply chain investments across the country, describing it as a national project that is fully privately financed and vital for the UK's global economic positioning.
Correction 26 September: An earlier version of this story incorrectly stated the runway's estimated cost as £49 billion. This figure has been revised to reflect that it represents the total planned investment for the airport, including £33 billion for the runway.