Liberal Democrat MP for Twickenham and Teddington, Munira Wilson, along with several of her Lib Dem colleagues, including Sarah Olney, MP for Richmond Park, has written a letter to the Secretary of State for Transport, Heidi Alexander MP, regarding her concerns towards plans for a third runway at Heathrow.

The letter writes: "We are extremely concerned about recent news reports indicating that the Government plans to endorse Heathrow expansion, with the Chancellor having said that economic growth "trumps other things".

"We, and many of our constituents, are very concerned that these "other things" are the environment and human health.

"We believe, further, that the stated economic benefits of expansion have not been proven. At the World Economic Forum in Davos, the Chancellor said that growth is the Government's "number one mission".

"Yet, there is ample evidence that the economic benefits of Heathrow expansion have been overstated. The New Economics Foundation (NEF) has highlighted serious flaws in the economic case for expansion, maintaining that the potential economic benefits, including on tourism and business travel, have declined significantly since the Department for Transport last assessed them."

It continued: "The NEF research also highlights the risk of worsening inequality in the UK under airport expansion.

"It is important to state that we all recognise and appreciate the value that Heathrow brings not only to our communities, but also to our capital city and country as a whole.

"The crucial point is that a third runway, combined with sweeping changes proposed by Airspace Modernisation plans currently under consideration, could make the impact on human health and the environment significantly worse.

"Back in 2020, Keir Starmer, when explaining why he had voted against Heathrow expansion in a vote in Parliament, said, "There is no more important challenge than the climate emergency".

"Indeed, it is difficult to see how Heathrow expansion can possibly be compatible with the Government's (rightly) ambitious goal of cutting greenhouse gas emissions by 81% by 2035.

"London is already the most overflown city in Europe. Heathrow is the single largest polluter in the UK, and its emissions account for over half of all UK aviation emissions.

"Yet, a third runway would see flight numbers increase by hundreds of thousands of flights a year. Heathrow expansion will only make the climate and environmental impacts worse.

"The impact on human health should also not be underestimated. A 2023 study from Imperial College London and the University of Leicester found that living near Heathrow Airport could increase people's risk of heart disease.

" A wide body of evidence also points to an increased risk of strokes, extreme mental health issues, substance abuse, heightened stress and chronic insomnia.

"We are particularly worried about research showing the negative consequences of aircraft noise on children's health and development.

"With pressures on the NHS already stretched to unprecedented levels, surely the negative health impacts of aircraft traffic would only add to this burden.

"It is our understanding that Labour's position – both in Opposition and in Government – has been to only support Heathrow expansion if four 'tests' (including on noise, air quality, climate and delivering countrywide economic benefits) are satisfied."

It added: "We are therefore writing to urge you in the strongest possible terms to clarify how and whether a third runway at Heathrow could meet the Government's four tests. We would also like to see the economic case reassessed.

"Both the economic and the environmental case for expanding Heathrow are in tatters.

"As the final decision on Heathrow expansion would lie on your desk as Transport Secretary, we are ultimately asking you, of course, to reject these plans.

"We would like to see a better Heathrow, not a bigger one. Many thanks in advance for your consideration, and we look forward to receiving your response."

Richmond Council has also expressed its concerns regarding Heathrow's plans.