Will the development of Heathrow’s third runway ever take off?

Ben Young, Intern
17/02/2025

Standing in Oxfordshire in late January, Rachel Reeves announced a series of initiatives in what has been dubbed her ‘Growth Speech.’ Central to her vision is the controversial proposal to expand Heathrow Airport with a third runway, a project that has been mired in debate for years.  A prolonged, likely fiery battle is going to play out over the airport’s expansion, which may prove to be a test of the government’s convictions. 

The expansion, estimated to contribute £61 billion to the economy over 60 years and create 77,000 jobs during its construction, is emblematic of the broader tensions between economic growth, environmental sustainability, and the challenges of navigating Britain’s restrictive planning regulations.

One of the most vocal critics of the Heathrow expansion is Sadiq Khan, the Labour Mayor of London and a former MP. Khan has condemned the project, citing environmental and noise pollution concerns. It is an unfortunate own goal for Labour, giving the opposition the ability to highlight the internal divisions within the Labour Party on this issue as one side pushes for economic growth, while the other prioritises environmental sustainability. 

Given the widespread unpopularity of Khan’s environmental activism with the Ultra Low Emission Zone (ULEZ) charge, it’s not surprising the government will brush aside his objections. Khan is likely to spend the rest of his third term raising hell about the runway to the disappointment of his electorate. His opinion on the runway appears incongruent with Londoners who want to see spades in the ground on a plethora of projects to improve access to housing, connectivity and infrastructure. 

The environmental argument against Heathrow’s expansion is compelling. Aviation is already one of the most carbon-intensive industries, adding another runway would significantly increase the number of flights, leading, ultimately, to higher greenhouse gas emissions. While the aviation industry is investing in greener technologies, such as sustainable aviation fuels and more efficient aircraft, these innovations are not yet advanced enough to fully offset the environmental impact of expanding Heathrow’s capacity.

Another major obstacle to the Heathrow expansion is the phenomenon of NIMBYism—an acronym for “Not In My Backyard.” This term refers to individuals who oppose development projects in their local area, often due to concerns about noise, pollution, or the loss of green space. NIMBYism has become deeply ingrained in Britain’s social fabric and is frequently blamed for the country’s burdensome planning regulations and sluggish economic growth. The Heathrow expansion would require the demolition of homes and the displacement of entire communities, further fuelling opposition from residents. However, public patience with NIMBYism appears to be waning, as the government seeks to address the UK’s infrastructure deficit by building new homes, reservoirs, railways, and, yes, a new runway. As one user on X succinctly put it: “If you moved to the Heathrow area prior to 1946, you have my deepest sympathies. If you moved anywhere near the place after 1946, you’ll have to just cry harder.”

It is worth noting Heathrow is doing a remarkable job already with its current two runways. It is the busiest airport in Europe, the only other European airport in the top 10 is Istanbul with its advantageous connections to the Middle East and Asia. Amsterdam Schipol airport has an incredible six runways but carried 17 million fewer passengers in 2024. Heathrow is one of the nation’s most efficient assets, acting as a hub between Europe, the Americas, Africa, the Middle East and beyond. Given this, why would anyone who has an interest in Britain’s economy oppose the expansion? If a fraction of the benefits mentioned become reality, then the political pains involved in bringing the project to fruition will be worthwhile. 

For the government, supporting Heathrow’s expansion is more than just an infrastructure decision – it is a statement of intent. It signals Britain is open for business and ready to compete on the global stage. Heathrow is not only the UK’s largest airport but also a major employer and a critical gateway for trade and tourism. Yet, despite the economic arguments in favour of the third runway, the project remains deeply contentious. 

If the government succeeds in delivering another runway, it will set a precedent for other large-scale infrastructure projects and demonstrate the UK can overcome its chronic indecision on major investments. If it fails, the Heathrow expansion will join a long list of ambitious projects that never came to fruition, further eroding public trust in the government’s ability to deliver on its promises. The stakes are high, and the outcome will have far-reaching implications for the future of the UK’s economy and environment.