After decades of debate and legal challenges, the UK government has once again thrown its weight behind the expansion of Heathrow Airport, approving plans for a long-contested third runway. The announcement, made by Chancellor Rachel Reeves, is part of a broader economic growth strategy aimed at boosting the country’s connectivity and competitiveness on the global stage.
1. A long and winding runway
The proposal to expand Heathrow, Europe’s busiest airport, has been on the table for over 20 years. First publicly announced in 2003, the plan has faced fierce opposition from environmental groups, local communities and political leaders across the spectrum. Over the years, the project has seen dramatic reversals, from government approvals to legal blocks and even a 2020 Court of Appeal ruling that declared the expansion unlawful due to its failure to consider the UK’s climate commitments. The Supreme Court later overturned that decision, paving the way for reconsideration.
The years of delay have kept Heathrow at capacity. In 2023, the airport handled nearly 84 million passengers, the highest in its history. Supporters of the expansion argue that a third runway is essential to maintain the UK’s status as a global business hub and to connect with emerging markets that currently lack direct flight routes.
Chancellor Reeves framed the decision as a crucial step for economic growth, arguing that Britain must “become the world’s best-connected place to do business.” She emphasized that lack of airport capacity is restricting opportunities for trade and investment, stating that “there are emerging markets and new cities around the world that we aren’t connected to because there aren’t the slots at Heathrow – or indeed any other airport – to fly to.”
For 14 years of Conservative government, we accepted low expectations and accepted decline.
— Rachel Reeves (@RachelReevesMP) January 29, 2025
We no longer have to do that.
This Labour government will drive growth in all corners of our country. pic.twitter.com/quwYNpgUjV
“This is the bold, responsible vision the UK needs to thrive in the 21st century, and I thank the Government and Chancellor for their leadership,” Heathrow CEO Thomas Woldbye commented on the Chancellor’s announcement. “[The third runway would] give airlines and passengers the competitive, resilient hub airport they expect while putting the UK back on the map at the heart of the global economy. With strict environmental safeguards, it would demonstrate that by growing our economy responsibly we can ensure our commitments to future generations are delivered.”
2. Opposition
The UK has legally committed to achieving net zero emissions by 2050 and critics say that increasing flight capacity directly contradicts those goals. Non-profit group Transport & Environment labelled the announcement “dystopian”, arguing that major airports should be focusing on reducing emissions rather than expanding capacity.
Among those arguing against the expansion is also Mayor of London Sadiq Khan, who has warned that the project will bring significant disruption and fail to deliver the economic benefits its supporters claim.
Moreover, the expansion could have significant implications for communities living in the airport’s vicinity, particularly in the areas of Harmondsworth, Sipson and Longford. Entire neighbourhoods might need to be demolished to make way for the third runway, with estimates suggesting that up to 750 homes could be affected. Beyond displacement, the expansion is expected to increase noise pollution for thousands of residents in West London and surrounding areas.
I can’t support plans to expand Heathrow which would damage our environment and place huge demand on our transport infrastructure.
— Mayor of London, Sadiq Khan (@MayorofLondon) January 29, 2025
The number of people already affected by noise is more than at Paris Charles de Gaulle, Madrid, Munich, Frankfurt, Amsterdam combined. pic.twitter.com/iA4epVoFzC
Meanwhile, conservation groups have criticized Chancellor Reeves’ broader approach to planning reform, particularly her remarks about easing environmental restrictions for developers by allowing them to pay into a nature restoration fund rather than meeting stringent ecological requirements.
3. Not yet a done deal
While the government’s endorsement marks a crucial step forward, the runway’s construction is far from certain. Heathrow’s expansion plan must still go through another round of government assessments this summer, with a final proposal likely to require a parliamentary vote. Given the history of political divisions on the issue—including opposition from high-profile figures such as former Prime Minister Boris Johnson—the project could still face significant obstacles in the House of Commons.
Even if approved, construction of the third runway is unlikely to begin for several years, as the airport would still need to go through a lengthy and complex planning process. If everything goes well, construction could begin by the late 2020s, with completion expected sometime in the early to mid-2030s.
In the meantime, more legal challenges are also expected. Environmental organizations, local councils and advocacy groups have repeatedly taken Heathrow’s expansion to court and new lawsuits could emerge given the UK’s legally binding climate commitments.