We strongly disagree with the assessment that expansion is necessary. Aviation accounts for a growing percentage of the UK’s carbon footprint and the sector needs to urgently contract if we are to meet our internationally-agreed targets for halting climate change. In a summer when drought and wildfires are sweeping the UK and Europe, approving new aviation capacity is a hugely retrograde step for communities and the climate. It also risks embedding the infrastructure of harmful biofuels into our transportation systems.

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

We disagree with the standards by which the government is measuring air quality impacts. It is clear to us that the attitude to air pollution is overly lax, with UK upper limits for nitrogen dioxide four times as high as those set by the World Health Organisation. Air quality outcomes of a Third Runway should be reassessed in line with WHO guidelines.

Noise

We feel strongly that it is impossible to make any accurate prediction or measurement of noise impacts from a third runway when new flight paths have not been published. This means that local residents cannot plan or anticipate the ways in which they will be affected by noise pollution, which is a serious problem and health hazard across the world. Chronic exposure to aircraft noise pollution raises risks of heart disease, high blood pressure, hearing loss, insomnia, anxiety and aggressive behaviour. Given the lack of available information on flight routes alongside the well-known negative consequences of sound pollution, the precautionary principle should apply and the Third Runway should not be constructed.

Climate change mitigation

This is the area where it is most abundantly clear to us that the severe consequences of airport expansion have not been seriously considered in this planning decision. Aviation is a hugely polluting industry that contributes both to CO2 and to non-CO2 warming of the climate. Demand reduction is urgent and non-negotiable if we are to safeguard a livable future. Promises of ‘SAF’ are just that – promises, empty and unlikely to lead to any meaningful, scalable, sustainable fuels in the long-term.

HEFA, the biofuel most commonly used for aviation, and the only one currently available in large quantities, has huge sustainability problems. Rainforests are routinely logged for industrial feedstock plantations (usually oil palm or soya) in Southeast Asia and South America. This reduces rainfall and releases huge emissions of carbon that were previously stored in the habitat, as well as decimating local biodiversity and weakening entire ecosystems. Even when already extant farmland is converted to a biofuel monoculture, this often just displaces the previous product (such as beef ranching or timber) onto uncleared forests. Similar practices of clearance occur on peat wetlands in these regions, which are drained or burned in order to capitalise on their rich fertile soils. This has an even more deleterious effect on emissions, since peat lays down its carbon stores over centuries. This results in an overall life cycle carbon footprint for biofuels that is higher than that of the fossil fuels they are designed to replace. There are also serious impacts on local biodiversity, food security and community land sovereignty, with indigenous or peasant farmer communities routinely disadvantaged, exposed to toxic agrichemicals, or forced to leave their ancestral lands altogether.

As a result, the government has rightly capped crop-based biofuel use in SAF and plans to rely on waste products like used cooking oil and palm oil mill effluent. However, risks and negative externalities remain with these feedstocks. Firstly, regardless of the kind of oil used, biorefining is highly dangerous due to the use of flammable, explosive hydrogen used to treat the feedstock at high temperatures, exposing workers to unjustifiable risks in a regulatory environment that has often not caught up with the transition from petroleum. Secondly, there is increasing evidence that what is marketed as waste oil is often anything but. Supply chains for these oils are opaque and often convoluted, involving unstandardised names and sale codes and often multi-country routes from supplier to purchaser. Producers are reliant upon voluntary and industry-captured certification bodies for their sustainability credentials, and there is clear evidence large-scale fraud is taking place within these systems. Crude vegetable oils are often passed off as wastes, while points of origin are rarely verified in person. Indeed, the issue is so widespread that Biofuelwatch was contacted by several whistleblowers, and arrests have been made in Indonesia.

Since it is impossible to say with any confidence that a given quantity of oil is truly a waste product, all sustainability concerns that apply to crude vegetable oil can be applied to UCO, POME and other wastes and residues as well. Even if we could be confident that all so-called wastes were true wastes, there simply would not be enough available to meet the UK’s skyrocketing demand for aviation fuel. Indeed, even using crop-based biofuels, there would be a squeeze on land – it would take 68% of the arable area of the UK just to meet our needs for SAF, massively crowding out dietary staple crops. Biofuels currently make up about 0.3% of all aviation fuel, and exponential expansion seems neither likely nor desirable.

For all these reasons, it is crucial that Heathrow, and other airports in the UK, not be expanded. Rather, there should be a rapid but just capacity reduction at all airports. In 2025 the Environmental Audit Committee made it clear that airport expansion risks the government’s own Net Zero targets.

Economic growth across the country

We strongly dispute that a Third Runway would bring growth to the UK, or that any benefits would be evenly distributed. Rather, homes will have to be destroyed and the M25 rerouted, moving people out of the area. Most jobs created will simply be those displaced from elsewhere in the UK, and most people travelling via Heathrow will not keep their money within the country long-term. The New Economics Foundation estimates a net negative economic impact from this project.

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.

We strongly disagree with this designation – we see it as little more than a strategy to exempt Heathrow from binding climate targets. The extreme weather, food shortages, increased likelihood of zoonotic disease and potential breakdown of infrastructure that the UK will face in the coming decades if climate change is not addressed are a far greater threat to the robustness and resilience of the economy than any imagined loss from not expanding Heathrow. The government would be better served by designating our crucial farmland or carbon-sequestering nature reserves as critical national infrastructure, and bearing in mind that there is no growth on a dead planet.

Many thanks for your time. We hope you will take seriously our objections and those of countless other organisations, experts and concerned citizens across the UK, and rethink this wrongheaded and reckless expansion proposal. More information can be found on our website, and those of the Stay Grounded Network, Flight Free UK, and No Airport Expansion.