London mayor refuses to act to block Heathrow expansion

Despite running on a platform to halt any further expansion of Heathrow Airport, on Thursday 16 January during Mayor’s Question Time, Sadiq Khan dismissed multiple invitations from Green Party AM Zack Polanski to work together in pursuit of that shared goal.

Heathrow expansion: still in the works

At the core of Heathrow’s expansion plans is the construction of a third runway. Initially proposed over two decades ago, the plan seeks to increase Heathrow’s capacity by accommodating up to 700,000 flights annually, compared to its current cap of 480,000. This expansion would allow Heathrow to handle an estimated additional 50 million passengers per year.

Of course, one of the most contentious aspects of the Heathrow expansion has been its environmental impact. Critics have long argued that adding a third runway would significantly increase carbon emissions at a time when the UK has set legally binding commitments to reach net-zero emissions by 2050. The additional flights, coupled with construction emissions, pose a substantial challenge to these climate goals and would exacerbate the climate crisis.

Meanwhile, the Heathrow expansion has faced numerous legal battles and political hurdles over the years. In 2020, the UK Court of Appeal ruled that the government’s approval of the third runway was unlawful because it failed to account for the country’s climate obligations under the Paris Agreement. However, this decision was overturned by the Supreme Court later that year, allowing the project to proceed.

For and against

As of early 2025, the Labour Party government has expressed conditional support for the expansion, contingent on meeting stringent environmental standards and securing broader public backing.

Proponents of the expansion argue that it is vital for the UK’s economic future. Heathrow’s role as a global hub supports thousands of jobs directly and indirectly, and the additional capacity could generate billions of pounds in economic benefits. Increased connectivity is seen as crucial for trade, tourism, and maintaining London’s status as a leading financial center.

However, opponents highlight the significant costs associated with the project, estimated to exceed £14 billion. They also point to potential disruptions for local communities, including increased noise pollution and the need to relocate homes and businesses.

Local communities near Heathrow have expressed mixed reactions to the expansion plans. While some see the potential for job creation and economic revitalization, others are concerned about noise pollution, air quality, and the loss of green spaces. The proposed expansion would require the demolition of parts of several villages, including Harmondsworth, raising questions about fair compensation and community well-being.

Labour what?

Currently, as the Financial Times reported Keir Starmer’s cabinet are split over whether to approve the Heathrow expansion:

Bosses at Heathrow, which handles more than 80mn passengers a year, are putting the final touches to their first expansion plan since the pandemic, but will not include a third runway at this stage, said people familiar with the matter.

Downing Street and the Department for Transport said they were “open-minded” about a third runway, but only if it satisfied four tests: delivering growth across the country, meeting climate obligations and complying with air pollution and noise considerations.

But one political aide said the cabinet was divided. “It’s no secret that there isn’t universal backing for the third runway, it’s just not a priority right now. [Energy secretary] Ed [Miliband] is the most obvious example of someone who is anti, but there are others who are uncomfortable about expanding Britain’s biggest airport,” the person said.

So, on that Polanski pushed Khan on 16 January over the Heathrow expansion.

Yet when prompted to join forces in lobbying government against any approval of the Airport National Policy Statement (ANPS), the Mayor repeatedly dismissed, and even mocked, Zack’s outstretched hand:

Reflecting after the exchange, Green Party London Assembly Member Zack Polanski said:

Expanding Heathrow Airport would be dangerous, even deadly, for every Londoner interested in breathing clean air or swimming in the Thames anytime in the next century.

The Mayor ran on a campaign promising to oppose Heathrow expansion, yet when I present him with opportunity after opportunity to take action, he refuses to engage with me.

Why won’t the Mayor work across party lines to stop Heathrow expansion in its tracks?

Featured image via screengrab