Heathrow consultation response

This consultation on the expansion of Heathrow Airport with a third runway is open until 1st September 2026. We have used a template from Campaign Against Climate Change to draft this response.

This response is on behalf of the charity Flight Free UK

We believe that expansion at Heathrow should not go ahead. Additional emissions from flights will endanger the UK’s climate targets, particularly with many other UK airports already expanding. The UK should prioritise infrastructure to make us more resilient to climate change impacts, to cut emissions and to reduce our dependence on fossil fuels, not high-carbon infrastructure such as flying.

To what extent do you agree or disagree with the assessment of the need for the proposed expansion of Heathrow Airport? Explain your answer.

We strongly disagree with the assessment of the need to expand Heathrow Airport for the following reasons:

Emissions:

Heathrow airport is already the single largest polluter in the UK. The Climate Change Committee has proposed a pathway for reaching the UK’s legally binding climate commitments and a third runway would almost double aviation emissions compared to the CCC’s proposals. 

We understand that support for Heathrow expansion relies on emission mitigation measures as set out in the Jet Zero policy. But there is huge doubt among climate scientists and aviation analysts that Jet Zero will achieve net zero aviation emissions by 2050. We believe that Jet Zero is overoptimistic and leads decision-makers to think that aviation emissions are accounted for, therefore expansion will bring no climate harm. We believe this to be false (detailed below).

Noise:

A 2013 study found that people living under the Heathrow flight path were 10-20% more at risk of stroke and heart disease than those not living under the flight path. Even though modern aircraft are more efficient and quieter, an additional runway and an increase in flights will increase the number of overflown communities and increase noise levels overall. 

Wildlife and community:

Even if Jet Zero were to reliably reduce emissions, even if new improvements to aircraft were to reduce noise, the third runway would still significantly impact communities, wildlife and the landscape.

The airport’s own proposals would require thousands of homes to be destroyed – in the midst of a housing crisis.

The M25 will be rerouted – an extremely carbon-intensive and disruptive project in itself.

The river Colne will be diverted and parts of the Colne Valley will be destroyed. This government has previously spoken about the value of the Colne Valley to London’s health and to the community’s wellbeing. The precious and rare chalk stream habitat of the Colne Valley is already under immense pressure from pollution, over-extraction and chemical runoff, which will only get worse if the third runway is built.

This government has also spoken of the benefit to the economy of the Colne Valley. Is this loss being offset against the supposed economic benefits of Heathrow expansion?

Economy:

The DfT’s own analysis shows that Heathrow expansion will not bring the economic benefits hoped for, with the net present value of the scheme between -£23.4bn and -£62.5bn.

Economic arguments revolve around more business opportunities, but business flights have been flatlining at 10% or less for the past several years, and fell to 7% after Covid. The main reason we fly is on holiday or to see family and friends (64% and 25% respectively, according to ONS), and airports take more money out of the economy than they bring in, with UK residents taking £78.6 billion out of the economy in 2024, vs foreign tourists bringing in £32.5 billion.

Failing to take climate action will lead to massive economic harm, which will dwarf the 0.05% GDP (maximum) that a Heathrow third runway is predicted to add to the UK economy by 2056. This summer’s heatwaves are an indicator of the harm we might expect to see in the future.

The government has proposed four tests which must be met for expansion to proceed. To what extent do you agree or disagree with how the government has set each of the ‘four tests’?

Air Quality

The impact of a third runway cannot be assessed using outdated air pollution limits. Currently the UK’s legal limit on NO2 is twice as high as the EU’s, and 4 times as high as the health based recommendations of the WHO.

Noise

Noise from flights is a serious health problem. With an increase and change in flight paths from the additional runway, many more communities will inevitably be affected. However, the flight paths won’t be published before the decision is made, so communities are being asked to respond without knowing exactly how they will be affected.

Climate change mitigation

The assessment of climate impact is seriously inadequate, primarily in its reliance on Jet Zero:

It assumes that the Jet Zero strategy will successfully reduce aviation emissions. Currently there is no reason to believe that any of the measures within Jet Zero will achieve significant and genuine emissions reductions.

Jet Zero relies on sustainable aviation fuel (SAF) which are claimed can reduce emissions by 80%. But this should not be taken as read. Biofuel pathways take into account land use change, but not from wild or forested land. If land is being taken from high carbon sequestration to mono crops, it is highly likely that the overall emissions will have no reduction at all. For this reason, the governmental policy has previously been not to allow biofuels to be used as SAF – but this requirement has recently been relaxed. 

All other pathways for SAF production are currently used for other, more efficient uses, e.g. used cooking oil in the road fleet, and animal fats for pet food. Diverting these to SAF not only increases the levels needed, because aircraft are much more energy-intensive and fuel-hungry than road transport, but also creates a hole in the market elsewhere that needs to be filled, potentially by first generation fossil fuel. 

Jet Zero also relies on carbon offsetting, sequestration and removal, but research has shown that the vast majority offsetting schemes don’t actually reduce emissions, and the engineering solutions to remove CO2 from the atmosphere are expensive, energy-intensive, and difficult to scale up to the required level. 

Jet Zero does not take account of the warming impact of non-CO2 effects including contrails, which are estimated to triple aviation’s climate impact.

Rather than assume savings under SAFs and Jet Zero, the government should wait to see if these measures are successful in reducing emissions at current capacity, before approving new capacity. 

Economic growth across the country

There is considerable evidence that Heathrow expansion will not lead to economic growth around the country, and in fact will have a negative effect outside London and the south east. Analysis by NEF (the New Economics Foundation) estimated that there would be 15,200 jobs lost in the wider regions of the UK and displaced to London and the south east. 

In the cost benefit analysis, almost all the benefit is shown as being to passengers using the airport, rather than the wider community, and this benefit is vastly outweighed by the negative impacts, so the overall net present value of the scheme is calculated as between -£23.4bn and -£62.5bn.

To what extent do you agree or disagree with the proposed designation of Heathrow expansion as defined in the draft HENPS as Critical National Growth Infrastructure (CNGI)? Explain your answer.

Heathrow expansion should not be designated as Critical National Growth Infrastructure as this would seriously prejudice the decision making process. It would prevent proper examination of how weak the economic evidence is in favour. 

This designation could make the third runway impossible to challenge in the planning process, however much evidence is provided of high levels of harm to the climate and to local communities. As long as the developer planned to put in some effort to reduce these harms, it could be approved because it was already designated as ‘critical infrastructure’, despite the harms outweighing the benefits.

This response uses the template drawn up by Campaign Against Climate Change. Respond to the consultation yourself by using the guidance here.

Deadline: 1st September 2026