Written evidence

Written evidence submitted by the Aviation Environment Federation (HEN0046)

Introduction

Aviation Environment Federation (AEF) is a UK-based national NGO focused on

reducing aviation’s environmental impact, particularly in terms of climate change, noise and air pollution. Internationally, we are a leading representative of the NGO grouping ICSA (the International Coalition for Sustainable Aviation) which has observer status to the UN’s International Civil Aviation Organisation (ICAO). We represent an active membership comprising local community and amenity groups living under flight paths and around the UK’s airports, including Heathrow.

We welcome this inquiry by the Transport Select Committee to scrutinise the draft Heathrow Expansion National Policy Statement published by the Government in June 2026.

a. The extent to which the draft HENPS provides clear and coherent guidance to the Secretary of State about how to assess a proposed scheme

While the HENPS framework has a very detailed list of requirements for scheme promoters to mitigate some of the environmental harms, we do not believe that it is coherent or provides the same level of certainty for each of the areas assessed. For example, the air test is only to meet legal limits, and not to protect the health of the local population by stopping them being exposed to increased air pollution (or to maintain the recent improvements seen in the area’s air quality due to the transition to EVs), and the economic test does not require the scheme promoter to show what it is doing to prevent the likelihood of jobs and investment being sucked from the regions. In some cases, the government is failing in its duty to protect communities from very real harm by relying on private companies to set the limits of what can be achieved. We would prefer if clear, measurable limits are presented, rather than a set of obligations for the scheme promoter to show it has attempted to meet through suggested mitigation. If the CNGI designation goes ahead, the scheme promoter is only required to come back at the DCO stage to show what it can do to try to mitigate harms, leaving no-one ultimately responsible for protecting communities and the health of everyone who lives around the airport.

b. The robustness of the Government's evidence and rationale for the need for a third runway at Heathrow Airport

The need case for the third runway rests largely on an unsubstantiated view that increased airport capacity and aviation automatically generates growth. We do not believe that the government has presented evidence in the HENPS that truly supports this assertion. The need case section of the HENPS implies the UK is suffering from a stifling lack of flights and airport infrastructure, yet goes on to highlight London and the UK’s disproportionately large aviation sector: e.g. ‘London serves more airport destinations with regular passenger services than any other city in Europe.’ The UK has a mature aviation market, with most passengers now travelling for leisure. Even at Heathrow airport, only about 18% of passengers are travelling for business, and that figure has been on a steady downward trajectory since 2008. We do not see evidence in the HENPS of how facilitating more people to leave the country and spend money abroad is good for growth in the UK - especially as we know the current tourism deficit is approximately £42bn, and the UK domestic tourism industry is struggling. While there is some merit in the argument that facilitating trade and connectivity as a whole can be beneficial to an economy, there is no justification in the HENPS of why this needs to occur at Heathrow and not other key UK airports.

The assertion that ‘the whole London airports system is forecast to be full by the mid to late 2040s’ does a lot of heavy lifting - is it really the case that the possibility that London airports could be fully used around 2050 necessitates pursuing an extremely damaging infrastructure project today, especially one that has proven to be so sensitive to world events like the Covid-19 pandemic and energy markets? This is all despite expansions at Stansted, Luton, Gatwick, Southend and London City being undertaken which more than cover the Airport Commission’s recommendation for increased airport capacity in the South East. The continued reliance on the conclusions of the Airport’s Commission in the HENPS is therefore surprising. The HENPS goes on to outline how expansion is necessary to maintain Heathrow’s hub competitiveness. However, Heathrow has managed to maintain its place as one of the premier international airports globally despite operating fewer air traffic movements in 2024 than in 2004. At the same time 16.5m additional passengers per year have been added and Heathrow now serves ‘over 200 destinations worldwide with a regular service’.

The conclusion that the main beneficiaries of expansion will be consumers (ie. passengers) needs to be set in context. At least 40% of people do not fly at all in any given year in the UK, and the government’s own figures suggest that about 70% of passengers do not use Heathrow Airport. This is a social justice question, delivering more benefit for higher-income consumers who wish to travel for leisure purposes. Similarly, there is little consideration of what effect expansion will have on capacity at other airports, or evidence to support assertions that Heathrow will deliver regional growth. We do not believe that a need case for the third runway can be constructed by just talking very generally about why people need to fly - particularly when the substantial environmental, social, health and community costs of this are simply ignored.

Defending Heathrow’s hub status and competitive position with regards to other hub airports such as Dubai and Frankfurt also does not appear to be of much benefit to anyone other than Heathrow’s foreign-owned shareholders. Again there is no real new analysis in the HENPS to justify why this growth has to occur at Heathrow - the HENPS invokes the importance of offering choice and competitive benefits to consumers by airlines being able to choose the best routes, but ignores the fact that Heathrow is currently one of the most expensive airports in the world for passengers to use, and its regulated asset base model allows it to operate as a quasi-monopoly. Throughout the need case there is a lack of detailed data and analysis to justify expansion, for example, statements such as: ‘without expansion, passengers are likely to suffer from higher fares’. Whilst this is possible, it ignores the fact that the costs of expansion will largely be borne by passengers as higher landing and passenger charges are used to recoup the investment.

c. Whether it is appropriate for Heathrow expansion to be designated as Critical National Growth Infrastructure

We strongly disagree with the proposal to designate Heathrow expansion as Critical National Growth Infrastructure (CNGI).

We understand that the CNGI designation, if retained in the final version of the HENPS voted on by Parliament, and therefore designated, would mean that there would be a strong presumption in favour of development at the DCO stage. We understand that the process to be as follows: At the DCO stage, the scheme promoter must show that the mitigation hierarchy has been followed on all four of the government’s “tests” (regional economic growth, air pollution, noise and climate). If the SoS is satisfied that the promoter has done enough, even if there are residual impacts (ie. the project will cause significant environmental harms which have not been mitigated), the CNGI presumption means that the SoS can still choose to grant planning consent. This will leave little recourse to mitigate the environmental harms once the DCO has been granted. In addition, subject to the developments in proposed planning law currently under consideration, there could also be a curtailment of the general right to judicially review the decision.

The “need” case

CNGI is a new designation that has not been discussed in any government documents before the publication of the draft HENPS. It is therefore yet to be subject to clear legal analysis and interpretation in the planning process. The CNGI policy starts from a presumption that development covered by the Heathrow Expansion NPS is critical to national growth (para 4.16 HENPS).

We strongly dispute the logical basis for reaching that presumption. The government has long maintained that the expansion of Heathrow must meet its four tests (UK-wide economic growth, not breach noise limits, not breach air pollution limits and align with UK’s legal obligations on climate change). The draft HENPS outlines what the scheme promoter needs to show to demonstrate it has met those tests, including having to demonstrate at the DCO stage that it will promote regional growth. However, notwithstanding this test, the Government puts the cart well before the horse and unilaterally declares, at this stage, before the scheme promoter has submitted anything, that the project will deliver growth. We believe this effectively renders the economic test obsolete.

We manifestly fail to see, from the evidence presented by the Government, how it could possibly be concluded that the project will deliver growth. The government’s own evidence base presented alongside the HENPS shows that the project will deliver an almost imperceptible level of growth over a 30-year timespan. Using a S-CGE model analysis delivered by Frontier Economics, which captures a wider range of economy-wide benefits than the Treasury’s Webtag model, the Department for Transport (DfT) assessment revealed that the project will deliver just 0.05% growth to GDP. This figure will not be fully realised until 2056, a full 20 years after the project is expected to open. This is ten times less than the Chancellor of the Exchequer claimed when the Heathrow expansion plan was dusted off in January 2025. In addition, the DfT’s analysis reveals that this growth will be heavily skewed in favour of London, with growth of 0.17% for London’s GDP, but less than 0.03%, and in some cases zero, for the UK regions outside of London. It is difficult to see how the project can be described as having critical national growth priority in those circumstances.

The government’s assessment of the “need” case for the airport appears to rest on the Airports Commission’s conclusions as the main source of evidence. It has updated the analysis and passenger forecasts as part of the HENPS and concluded that there remains strong demand for London airports. However, we do not believe the Airports Commission unequivocally provides the evidence the government claims it does. The Airports Commission quite clearly concluded in 2015 that there was a need for one more additional runway in the south-east as the solution to the capacity constraints facing the whole London airports system. During its 2 year inquiry, it looked at the passenger forecasts and different markets served by London Gatwick and London Heathrow. It concluded that the Heathrow North-west scheme should become that runway. However, in the intervening years, the government has given permission to Gatwick to go ahead with a second runway, and also allowed all the other London airports – Stansted, Luton, London City and Southend – to expand. Together, these provide the same, if not more, extra capacity as a third runway at Heathrow. We do not believe it is logical to discount the effect of allowing an additional runway at Gatwick on demand forecasts at Heathrow and vice versa – and we see no analysis of that impact on the seemingly unsubstantiated claim that the whole system will be full “by the 2040s”. In fact, AEF uncovered previous modelling by the DfT, undertaken for Jet Zero, that showed if Heathrow’s third runway went ahead, the additional demand case for Gatwick would collapse. The new DfT forecasts also build Heathrow’s third runway into the modelled base case, only providing information on how demand would develop with the existing 2 runway configuration deep in the annexed data sets, and making it difficult to assess the additionality of the project.

Furthermore, we do not believe that the positive economic benefits produced in the HENPS could lead to any kind of equitable national growth for everyone. These benefits almost exclusively accrue to passengers through consumer benefits unlocked through more flights to more destinations and at more convenient times. It is claimed that expansion may protect Heathrow’s “hub” status, but it is effectively a monopoly over passengers who need to change planes in Heathrow held by a fully-foreign owned private company. It is unclear how these claimed consumer and passenger benefits, or the protection of the hub status, will deliver any meaningful benefit for the estimated 40% of Britons who never fly in a year, or the more than 70% of passengers who do not fly through Heathrow airport.

We find the decision to quote the “£42bn” in benefit figure as the headline figure in the government press release selective and misleading, given that it only relates to passenger benefits (as above), and does not include the enormous monetised environmental costs. When these are included, the scheme’s Net Present Value (NPV) reduces down to between MINUS £23.4bn and MINUS £62.5bn over 60 years. We believe use of the Government’s figure for economic benefits misleads the public to justify the Government's support for the project and should not be given unequal weight in the planning balance, when the very real negative environmental impacts in terms of a massive increase in carbon emissions, noise and air pollution, homes lost and communities erased and gridlock on local roads, are simply ignored by the decision-making on CNGI.

The suggestion that increasing capacity at Heathrow will automatically lead to more domestic connections is a fallacy, as the airport has consistently cut domestic flights as they are less profitable than international routes. The fact that the PSO designation has to be created to protect many of these routes, and paid for by the government, should be sufficient proof of this. And the Airports Commission also concluded that regional connectivity could suffer unless slots were ringfenced (presumably with public subsidy).

The value of freight to the UK economy seems another fallacious justification. Little evidence has been supplied to support the value of freight to the UK economy. From a supply perspective, for dedicated air freight operations, East Midlands airport already serves as a cargo hub, and the government has, since the adoption of the ANPS in 2018, approved the opening of an air freight hub at Manston Airport, where the “need case” for extra freight capacity was disputed during the DCO process.

The “need case” for extra freight capacity at Heathrow is not sufficiently evidenced in the draft HENPS. Most of Heathrow’s cargo is taken in the bellyhold of planes, which means it is restricted to relatively small volume exports by weight such as gold or Scottish salmon. Aside from whether Scottish salmon needs to be sent via Heathrow before exporting, we do not believe that the government has presented evidence that there is suppressed demand for freight which would be unlocked with more capacity. Instead, the evidence presented is limited to the current values of bellyhold cargo. In fact, the aviation forecasts published alongside the draft HENPS do not present any forecast or analysis of freight trends.

We also do not follow the logic of claiming that the increasing capacity will necessarily lead to more resilience - para 2.35 admits that the serious power outage which occurred in 2025 “would not have been solved by increasing capacity”, and it may be necessary to increase power supply to Heathrow in the event of expansion, again putting extra strain on local networks. There are many things that can be done to make the airport more resilient in its current form, including investing in existing infrastructure, and the airspace modernisation programme, which has long been presented as the solution to delays and planes being stuck in holding patterns at Heathrow. And in any event, added capacity only provides a partial, temporal solution to improving operating resilience while a new runway is under-utilised: as traffic grows on the new runway, the same problems will emerge. Of course, by expanding the airport and emitting more carbon into the atmosphere, a third runway would lock in emissions for many years to come, and commit the airport to having to deal with much more extreme weather disruption in future.

In conclusion, Paragraph 4.18 states that CNGI is supposed to reflect the ability of expansion to support “economic growth objectives, together with national resilience, connectivity, freight, passenger and wider strategic benefits”. Given what we have stated in this analysis, we do not believe any of these thresholds have been met, and the only tangible benefit identified in the entirety of the HENPS and accompanying Appraisal of Sustainability is to a very narrow section of the UK population, namely passengers.

* These conclusions have been based on legal analysis we commissioned together with Friends of the Earth and Opportunity Green. Please contact us if the Committee would like to see this advice. Thank you

d. How effectively and robustly the draft HENPS sets out the assumptions and requirements of the Government’s ‘four tests’ for expansion, on:

● Economic growth across the country

The framework for decision making on the test on economic growth across the country is brief and lacking in detail. This is a surprise given that it is the only real justification given for why this project should be supported. Given the dire results of the economic assessment presented in the government’s own Appraisal of Sustainability, we would expect the scheme promoter to struggle to demonstrate that there will be any impact at all on the UK’s wider regions. The AoS showed that the project would not be able to generate more than a 0.05% boost to GDP, and this would not be fully realised until 20 years after the runway opens (2056). This exceptionally poor result derived from a S-CGE assessment, the very tool the HENPS recommends should be used to capture wider benefits. Moreover, this assessment, carried out by Frontier Economics, shows that under several different scenarios, the benefit to any of the UK’s regions outside London is less than 0.03%. In contrast, it is consistently 0.17% and above in London. Given these underwhelming results, we would expect the draft HENPS to require promoters to show explicitly how jobs and investment will be created in the regions, rather than simply relocating from the regions to London. We would also expect a) more detail on how regional routes to Heathrow will be guaranteed and paid for, and how these would support regional businesses, and credible reasons why regional businesses would choose to use Heathrow over other more conveniently located airports such as Manchester, b) a requirement to show that routes and passengers will not be diverted away from other UK airports, and c) an analysis of what wider economic impact that kind of redistribution will have on jobs and regional economies. The government’s accompanying AoS shows that for the first 20 years of operation, the growth at Heathrow comes at the expense of other UK airports. For example, Birmingham’s passenger numbers are forecast to be 7.5m lower in 2050 if a third runway opens, a 22% fall.

From the government’s own Appraisal of Sustainability (AoS), we get a rather negative indictment of what the Airports Commission also found ten years previously, that skills and investment flood from the “less productive” regions of the UK to the South-East. While the draft HENPS does require the promoter to show how it will “support economic activity” in the regions, it does not require the promoter to show how it will prevent jobs and investment flowing out of the regions and protect regional economies, jobs and businesses.

In a financially constrained world, with a skills shortage and a long list of other crucial infrastructure projects, we would argue that the Government should assess the “opportunity costs” of a 3rd runway scheme measured against other possible uses of that construction and investment capacity - even if it is a private sector project - to drive regional economic growth. For example, how does its overall utility and growth potential perform against alternative large-scale infrastructure projects such as Northern Powerhouse Rail, where those investment choices and construction jobs could be also well employed. The government’s own peer reviewer of the economic case for growth specifically highlighted that 88% of the GDP impact of the project is due to expenditure on construction, which could of course be used on national projects which benefit everyone, and not just a narrow section of the population who want to fly more.

● Air quality

The Government’s assumptions and requirements on air pollution are reasonably set out in the draft HENPS, although we disagree with the metrics assessed against (see below). We are satisfied that the requirements on the scheme promoter to show that the elements under its direct control, such as airside vehicles, emissions from auxiliary power etc are mitigated. However, despite the AoS showing clearly that emissions of NO2 from planes are increasing because aircraft are becoming larger (and larger planes are permitted to emit more NOx) and the priority given to CO2 reductions by manufacturers, there is no enforceable requirement in the HENPS for the scheme promoter to mitigate this. The document suggests that landing charges could be used to incentivise aircraft with fewer NO2 emissions, but this could contradict using landing charges to incentivise lower CO2. While we recognise a scheme promoter has limited levers over this issue, it does not remove the very real health dangers associated with increasing NO2 emissions, and we believe that the government should be ultimately responsible for reducing harms to our health.

We welcome the requirement for the scheme promoter to develop a surface access strategy and vision, and we welcome the acknowledgement that increased vehicle journeys to an expanded airport will cause massive congestion and air pollution for local residents. However, we would argue that the local communities require a lot more than a commitment to work with other bodies to deliver any upgrades to rail that will be required. Specifically, we find the phrase “how it expects to meet the costs of any rail schemes required to help deliver the proposed mode share targets” ambiguous, and leaves the door open for public money being spent on any shortfall to make up for scheme delays.

At the same time, there is no requirement for “all such rail enhancements” to be “comprised within the DCO application for the Northwest Runway scheme in order for development consent to be granted”. While we acknowledge that this is an enormous and complicated scheme, and the scheme promoter cannot be expected to take on the work of public bodies such as National Rail, we do not think this presents a sufficient guarantee. We believe that the scheme promoter must commit money to building the necessary rail connections, and without assessing the risk of those connections not materialising in future, it seems problematic to allow passenger numbers to increase by an additional 30m (up to 116m in total) without a full assessment of the deliverability of these guarantees at the DCO stage. The mode share targets are ambitious and we welcome them, but we feel the precise mechanics of how this so-called “backstop” would work in reality are vague - retrospectively applying planning conditions after the horse has bolted is no guarantee that local communities will be protected from significant health impacts associated with poor air quality and gridlock on local roads and motorways.

Importantly, we believe that the scientific and health basis for the government’s assumptions and requirements on air quality are hopelessly and dangerously out of date, and we are concerned the draft HENPS does not go far enough to protect the health and lungs of hundreds of thousands of Londoners and those living in Berkshire. The framing of the “air test” is merely to meet our current legal obligations, which have been scientifically shown to be inadequate. The World Health Organisation says that there is no safe level of air pollution, but recommends levels of NO2 should be less than a quarter of the UK’s current legal limit. Important progress has also been made in the EU where the WHO interim target of 20ug/m3 will be introduced in 2030. Assessing the impact of this project against the old 2010 legal limits when the scientific evidence on air pollution has exploded in the last 15 years, means that we are allowing local communities to be exposed to twice as much air pollution as the EU currently allows. This is especially concerning because such significant improvements in air quality have occurred in recent years, and this could all be put at risk. The Mayor of London has previously indicated that all of London should be on a pathway to meeting these health-based targets in the next few years. For that reason, we believe that while the draft HENPS rules superficially looks like it would lead to a legally watertight case on air, it will not lead to a morally watertight one.

In addition, the HENPS requirements on other pollutants of concern is very light - it is widely accepted that aircraft are high emitters of ultra fine particles (UFPs) which are associated with a range of health impacts, but there is no obligation in the HENPS on a scheme promoter to do anything to reduce, or even monitor, UFP emissions. This is contrary to the precautionary principle - legislators in the EU are moving towards regulation of UFPs, and it is likely the UK will have to follow suit at some point in the future. In addition, there is no requirement to assess the interaction of increased emissions of volatile organic compounds (VOCs) and NO2 at the airport, despite there being known associations with localised ozone formation incidents in West London.

● Noise

We do not believe that the information supplied in the noise section of the HENPS is adequate to allow the public to make an informed response. We believe the use of indicative flightpaths, especially those designed over ten years ago by the Airports Commission, is not good enough for communities who want certainty when they are responding to this consultation about whether they will face an increase or change in their exposure to aircraft noise. It is not logical or fair to push this proposal forward before there is any agreement about the impacts of the airspace modernisation process, which is a material consideration on how the impacts of noise will actually accrue to real people in the real world.

We do welcome the commitment to protecting community respite, the requirement to provide noise insulation and pay into a community noise fund, and the proposal for a 6.5 hour night flight ban. However, it still remains impossible for communities to assess if the mitigations proposed are adequate if they do not know the extent to which the third runway will affect them. These mitigations are based on the use of contours and noise envelopes, which again, are subject to change depending on the choice of flight paths and the allocation of traffic to each route, and so any proposals the scheme promoter makes at the DCO stage are unlikely to be a cast iron guarantee for all communities if the airspace modernisation process is not complete. Again it amounts to closing the stable door after the horse has bolted. We therefore suggest that there should be a requirement in the HENPS that a DCO cannot be granted before the airspace modernisation process has been completed for Heathrow’s flightpaths (including with a third runway), in order for communities and stakeholders to better assess how they will be impacted.

The need to engage the public more on noise (in the run up to the 2018 ANPS the Government held roadshows in the local areas to highlight the plans and associated impacts), is even more important given the recent ANAS and ANNE findings. These surveys of public reactions to daytime and night time aircraft noise exposure, published by the CAA and DfT respectively, show the UK public is highly annoyed at much lower levels than previously thought (and correlating closely with the WHO’s recommendations on noise exposure). We are disappointed that the results of the ANAS/ANNE noise studies have not been fully reflected in the draft HENPS. We are aware that the studies were finished several months ago, and it is reasonable to expect that they should have been incorporated fully into the noise appraisal. Instead, the reports are acknowledged only as a sensitivity test while noting that “Government aviation noise policy has yet to be reviewed in light of the newly published evidence”. But the results of the sensitivity tests are hugely significant, showing a four-fold increase in the area affected. By 2055, under the 3R scenario, the 43 dB LAeq contour is estimated to include 3,405,000 individuals and 1,495,000 households, representing a 33% increase compared with a two-runway airport. It is noted that this is less than the comparable 2024 estimate of 4,650,000 people and 1,876,000 households, but it highlights that much of the benefit assumed to come from quieter aircraft in the future will be eroded by the scheme, while many people will be overflown for the first time.

We do not believe that the Webtag assessment in the economic appraisal provided a monetised cost for the now approximately 3.4m people exposed to 43dB Leq 16-hour. If these numbers had been used to fully reflect the environmental costs of the scheme, the NPV of the scheme would have been even lower than the shockingly negative figure already identified. We also have no guarantee that the ANAS/ANNE levels will be reflected in future government noise policy. Given enormous numbers of people affected by noise from Heathrow compared to any other airport in the country, it seems premature and somewhat unfair to push forward the draft HENPS without bringing noise policy up to date to reflect the latest science first.

But even using the Government’s existing metrics and thresholds, the noise impacts of the scheme can’t be disguised. By 2055, the 51 dB LAeq contour for R3 is 50% larger than under the 2R scenario (9% smaller than in 2024), while at night, by 2055, the 45 dB LAeq contour is 41% larger than under the 2R scenario (4% smaller than in 2024).

Trust is an important factor in determining reaction to aircraft noise. It is important to note that similar commitments to reduce noise have been made in the past, including on nightflights and the provision of effective noise insulation. For many in local communities, these promises have been eroded or broken, and we are not sufficiently convinced from the wording of the HENPS that the night flight ban, the requirement to pay for quality insulation, or the guarantee of respite in the future, will be legally binding and stand the test of time.

● Climate change mitigation

The HENPS provides a detailed framework against which a scheme promoter should assess all the carbon impacts of the project. The assessment is set out with reference to solid international accounting principles and has a rigorous assessment of what should be considered. We welcome the clarification in this draft, compared to the vague language in the 2018 ANPS, that emissions from the aircraft using the new runway are the single largest source of extra emissions. However, we are disappointed that despite considerable scientific progress in understanding the impact of additional warming from contrails (more likely to form on the large number of long-haul trans-Atlantic flights using Heathrow), the government has required nothing more than a vaguely-defined “qualitative assessment” of non-CO2 emissions. We welcome the assertion that the scheme promoter must show significant investment in greenhouse gas removals - the need for which has almost doubled by 2050 (the 2022 Jet Zero modelling showed residual emissions of around 19MtCO2 in 2050 under the High Ambition Scenario, but the new 2026 Aviation Forecasts show, under a continuation of current trends, a figure of 41MtCO2).

Unfortunately, the accompanying AoS and the 2026 Aviation Forecasts present a virtually impenetrable hodgepodge of competing scenarios for consideration, most of which use differing baselines, modelling inputs and assumptions and conflicting appraisal timelines (sometimes up to 2055, sometimes 2050, sometimes 2040 and sometimes 2095). The comparison with emissions from a two runway scenario in 2050 are buried deep in an annex. All of this makes it difficult to place a finger on the key and relatively simple question everyone wants to know the answer to: what is the carbon impact of the additional emissions from the 3rd runway if it goes ahead?

It is of serious concern to us that there has not been any substantive change to the previous position that the UK’s aviation emissions are managed outside the scope of the HENPS (section 9.2.71 refers to “wider system mitigation”). This continues the problematic approach of the 2018 ANPS that the responsibility of the scheme promoter to do anything to mitigate emissions is minimal - it remains just a matter of a non-enforceable commitment to dealing with surface access and building/airside emissions. If the airport did not go ahead, there would be no need to mitigate the enormous impact of the emissions from the planes in flight. Yet the scheme promoter has very little to do to prove it is working to reduce emissions, and can largely rely on the government’s assurances that emissions are being managed nationally, all while gaining financially. Yet the Government has announced, in light of the new 2026 passenger and CO2 forecasts, that it will be reviewing the Jet Zero Strategy in 2027 (after the scheduled vote in Parliament to adopt the HENPS).

This question of how to quantify the emissions impact of a scheme continues to vex planning inspectors who, at recent DCO hearings, have struggled to interpret the significance that should be attached to aircraft emissions, relevant policies and tests. In this respect, we are disappointed to see that the troubling ambiguity of the previous section 5.82 “material impact” test lives another day. We have seen multiple attempts to understand what that test actually means in the real world, including a tortuous exchange during the Luton airport expansion DCO process. As a rule of thumb, the IMEA guidance has been relied upon previously, which generously recommends defining GHG emissions as “significant” if a scheme exceeds 5% of national carbon budgets. However, we still see no concrete reference to this in the HENPS, merely the continuation of the ambiguous “material” significance which will likely have the promoters’ planning lawyers rubbing their hands in glee.

Although this HENPS, and the accompanying Aviation Forecasts are undoubtedly a more honest assessment of the parlous state of aviation decarbonisation, and an acknowledgement that the techno-optimism of the 2022 Jet Zero Strategy must be tempered with a good dose of realism, the fundamental framework of decision-making for the Secretary of State remains intact from the 2018 ANPS. It absolves the SoS Transport of any real responsibility for the failures of policy to deliver the sectoral cuts in emissions necessary for us to meet our legislated carbon budgets, and merely requires their adequacy, or lack thereof, to be assessed against the whole economy trajectory (set by the SoS for Energy Security and Net Zero in a separate process of drawing up carbon budget delivery plans every 5 years). It also absolves the scheme promoter of any responsibility to ensure that UK aviation emissions are on a downward trajectory, while simultaneously inviting them to pursue a project that will send them in the opposite direction. With a project of this scale and size, it seems irrational to not present much more rigorous restrictions and limits on the amount of carbon emissions from the project at the DCO stage.

e. How adequate the information published alongside the draft HENPS is, including its accuracy, comprehensiveness and methodology, and how effectively evidence and data have been reflected in the draft HENPS, including on cumulative impacts

Alongside the draft HENPS the Government has published an Appraisal Of Sustainability covering noise, air quality, climate change, biodiversity, landscape and visual impacts, water resources and flood risk, impacts on people and community, and economics. Accompanying reports include the Habitats Regulations Assessment, the Equality Impact Assessment and the Health Impact Analysis. The DfT has also released updated UK passenger and CO2 forecasts. Overall, we welcome the adoption of more realistic assumptions relating to decarbonisation in the forecasts. This includes relating carbon pricing to UK ETS and CORSIA prices (at significantly lower levels than assumed in Jet Zero), reducing SAF from 50% in 2050 to 30%, and setting lower expectations for aircraft efficiencies. As a result, based on a continuation of current trends, the forecasts show CO2 from aviation increasing nationally to 41Mt in 2050 compared to 37Mt in Jet Zero. Even under a scenario with more ambitious ‘technology development’ emissions in 2050 are still 28MtCO2 compared to 19.3MtCO2 in Jet Zero’s high ambition scenario. This provides a more realistic baseline position.

The HENPS and accompanying reports may appear to cover the requirements and key issues, but in some cases the information is superficial and important information that could assist with interpreting the results has not been provided.

Passenger and CO2 forecasts. As R3 is built into the modelling baseline, it was very challenging to find a figure for what would have happened with the existing two runway scenario. This makes it difficult to assess the additional carbon from expansion. Some aggregated figures are provided in the main reports, for example the additional carbon between 2024 and 2095 and a comparison of the additional carbon from the project with carbon budgets, but the detailed breakdown is only provided in an annexed data set.

Noise. The noise impacts have been generated using indicative flight paths requested by the Airports Commission back in 2015. While it is acknowledged that the airspace modernisation programme is ongoing, not providing communities with reliable flight paths information during the public consultation seems flawed, especially when so many communities will be overflown for the first time.

Last year the CAA provided the DfT with the results of the ANAS study which revealed that people are highly annoyed by aircraft noise at significantly lower levels than previously identified in SONA (2014). SONA is the basis for the selection of the noise thresholds in the Appraisal of Sustainability for noise, although it does include a sensitivity test using ANAS and ANNE (for night noise). As noted earlier in this submission, the sensitivity results have a marked impact on the results, increasing the impacted area fourfold: by 2055, under the 3R scenario, the 43 dB LAeq contour is estimated to include 3,405,000 individuals and 1,495,000 households, representing a 33% increase compared with 2R. For comparison, the 2024 estimate is 4,650,000 people and 1,876,000 households within the 43 dB LAeq contour. These figures, representing the latest available evidence, should be the basis for consideration of the draft HENPS and its associated environmental costings and mitigations.

f. How robust are the methodology and data used for any forecasts or assumptions about the future underlying the analysis presented in support of the HENPS, and whether the range and use of scenarios in the document are appropriate

See previous answer

g. How comprehensive and realistic the requirements are in terms of environmental mitigation, supporting measures for communities who will be affected by expansion, and surface access to the airport

Noise - as previously indicated, we recognise that the proposed night time flight ban, the community fund and the proposed protection of respite should theoretically provide protection for communities. But without actual flight paths it is only possible to make generalised conclusions about their efficacy in protecting communities. We believe that there must be an obligation to publish actual flightpaths at the point of the DCO application, and we believe that the new ANNE/ANAS noise attitudes study should be formerly incorporated into the HENPS modelling, and fully monetised and costed into the Webtag assessment before we can truly understand the impacts of increased noise.

Air pollution - again as stated, assessing the air pollution impacts of the project against legal limits which are widely understood to be inadequate and out of date by the scientific community provides very weak protection and mitigation for local communities. The WHO has made it very clear that human health cannot be protected unless much stricter limits are adhered to - in the case of NO2 this is just 25% of the current UK legal limit. It is likely that the legal NO2 limits will change in future, reflecting the fact that the EU is already on a pathway to meeting the interim WHO targets by 2030. Basing mitigation on attainment of the old targets means condemning West London residents to breathe worse air than their European counterparts. It is also likely that there will be future regulation of UFPs, again the EU now requires UFP modelling at hotspots (often airports), and UK residents are not being offered the same protections. The Mayor of London has previously indicated that London should aim to meet the health-based limits of the WHO, and research has been conducted to assess the pathways required to meet those limits.

On carbon emissions, the HENPS repeats the mistakes of the ANPS by not establishing a clear obligation on the SoS for Transport to jointly share the ultimate responsibility for guaranteeing the 3rd runway development will not threaten our legal obligations to mitigate climate change. The nature of carbon budgets means this responsibility actually lies at the feet of the SoS Energy Security and Net Zero, effectively determining at a distance if the DfT’s policy on aviation decarbonisation will actually deliver the carbon savings required for a given carbon budget period. This effectively outsources responsibility, at a time when the DfT has announced a review of the Jet Zero Strategy in 2027.

It is abundantly clear from the new Aviation Forecasts that the Jet Zero Strategy needs rethinking. The forecasts now show total UK aviation emissions in 2050 to be 41MtCO2 in the “current trends” scenario. This reflects the lack of progress on key decarbonisation levers such as confidence in the long-term scaling of Sustainable Aviation Fuels after 2040 and robust carbon prices, and the virtual national policy void on greenhouse gas removals needed to contribute to closing the forecast 41Mt gap to achieve net zero for the sector. These “out of sector” mitigation measures will be driven largely by the Secretary of State for Energy Security and Net Zero. This fissiparous approach to bearing responsibility for the emissions, which so obviously arise from backing a project of this scale, potentially creates an accountability ‘doom loop’.

The Aviation Forecasts state there is no indication that net zero by 2050 cannot be achieved for aviation, but, in advance of the Jet Zero review, neither is there any evidence to substantiate that it can. The review of Jet Zero also makes it difficult to know the extent to which the scheme would “materially impact” our UK carbon budget obligations. In the meantime, the scheme promoter can point to these processes happening outside its direct control to mitigate the impacts of a scheme. In addition, the failure to require any mitigation measures to reduce non-CO2 emissions means that at least two thirds of the warming impact of aviation is not being mitigated at all.

h. How the Government’s decision to select the Heathrow Northwest Runway scheme to inform the review has affected the draft HENPS and is likely to affect potential promoters

We find it confusing that the “preferred” scheme was announced as the Heathrow Northwest Runway proposal submitted by Heathrow Airport Limited, but the HENPS has clearly been written with one eye on allowing competing promoters to come in with alternative schemes, potentially on a phased basis. The references to a staged development can only be referring to the rival Arora bid which was discounted by civil servants last year. This causes all sorts of problems, because we don’t know where the flight paths will be if the runway is further east than planned, we don’t know how many homes will be demolished or rendered uninhabitable, we don’t know which air pollution monitors may breach legal limits and we don’t know which local roads will face gridlock. We also don’t know what economic impacts will come from the possibility of a shorter runway being used for smaller, short-haul flights, instead of the more profitable long-haul routes than the original scheme proposed. In addition, if the window is open to building a longer runway in the future, there is scant information about how the environmental impacts of that scheme will be assessed.

i. How well the draft HENPS reflects Government policy on airports and aviation, and on other elements of broader a) transport, b) planning and c) climate and environment policy

If anything, the HENPS seeks to distance itself from wider aviation policy - changing the name from ANPS to HENPS suggests it has little or no application to other airports and is only about Heathrow. The impact on regional airports and the “need case” for other London airports under the Making Best Use (MBU) policy isn't clearly assessed, and we believe MBU should also be reviewed.

If government policy is restricted to a very narrow interpretation of carbon budgets and the UK’s Climate Change Act 2008, the draft HENPS suggests that there should be no problem meeting carbon budgets even if the the 3rd runway goes ahead, because it will be assumed that any increase in emissions will be met by an accompanying reduction in another economic sector. However, we see no requirement in the HENPS to assess whether this is really the case - as argued elsewhere, emissions are managed at the economy-wide level, by a different Secretary of State, and using different approaches to modelling aviation emissions (for example the treatment of SAF accounting in the CBGDP) that means they cannot be easily compared to Jet Zero.

j. To what extent the draft HENPS adequately takes into account changes in the context of airport expansion since 2018, such as, for example, current and future capacity at other airports, new legislative requirements, and developments in technology

As we pointed out earlier, the HENPS assumes that the 3rd runway is taking place in a vacuum, and that the “need case” has been established and is beyond discussion. However, a significant number of airports have been granted permission to expand in recent years - AEF analysis shows that since 2018, an extra 63mppa capacity has been approved by the government (Bristol +2mppa, Stansted +15.5mppa, London City +2.5mppa, Luton +14mppa, Gatwick +29mppa). At the same time, the government has granted permission for a new cargo hub at Manston Airport, very close to London. With the exception of Bristol, all the new airport capacity granted has been in the South East, where 61mppa has been granted, vastly exceeding the Airports Commission recommendation that the SE required extra capacity of one more runway (typically 45mppa).

k. Whether the draft reflects lessons learned from legal challenges to the 2018 Airports NPS

The legal challenge to the 2018 Airports NPS centred around the issue of whether the Government had taken its obligations under the Paris Agreement into consideration when determining the impact of the proposed third runway. The Court of Appeal established that the SoS had erred in his decision making by failing to take into account the “obviously material” consideration of the Paris Agreement’s commitment to attempting to limit warming to 1.5C, and subsequent to that court victory, the then SoS accepted that the third runway should have been assessed against the 1.5C. However, this was overturned on appeal at the Supreme Court. On face value, there does not appear to be any analysis in the draft HENPS about whether the project is compatible with the Paris Agreement’s 1.5C temperature goal, and the UK’s obligations to consider its international commitments. The HENPS only requires compliance with the CCA 08 and does not mention the Paris Agreement at all. It is unclear what this means in terms of what impact the project will have on the UK’s obligations to meet its NDC. It is also unclear what it means in terms of mitigating the impact of the project beyond 2050 when the CCA 08 is due to end and there will be no further carbon budgets. The DfT modelling goes out to 2095, and concludes that some 185Mt of emissions - 97% of the carbon impact of the project - will occur after 2050.

At the same time, has the government in fact learned something very useful from previous legal challenges - that it can bypass scrutiny by the courts by unilaterally designating a project CNGI which would effectively neuter future judicial reviews into DCO decision making?

l. The effectiveness of the Government's consultation on the draft HENPS.

We believe that this consultation is being rushed through at a difficult time of year for many stakeholders with an important interest in participating. The draft HENPS and accompanying documentation run to over a thousand pages, with several additional data sets, and were published just a few weeks before the summer holiday period. Not only is this challenging for us over the holiday period, it makes it difficult for MPs to participate, as they will be on recess during this period. While there is an obligation for consultations to run to at least 8 weeks, we do not think an extension to 10 weeks makes a material difference when considering the enormous amount of complex data in numerous separate documents and spreadsheets. As mentioned above, using differing baseline assessment years and numerous complex scenarios for modelling makes it extremely challenging to get a comprehensive picture of the economic and environmental impacts of the project.

Furthermore, we have been given very limited opportunity as civil society to discuss the inputs and assumptions underpinning the documents prior to the publication of the draft HENPS, despite repeated requests from NGOs and communities, both before the publication of the draft HENPS, and after. This means we have been unable to benefit from a clearer picture of the modelling assumptions to present a fully considered and comprehensive submission to the TSC.

In conclusion

We do not believe that the draft HENPS provides sufficient guarantees to local communities on the very real health impacts of expansion from noise and air pollution, nor do we believe it provides confidence that the UK’s climate change obligations will be met. We believe that the economic case as presented is so weak it would be irrational to conclude that all this devastation is possibly justified.

In addition, AEF recommends a number of new assessments that should be included in the draft HENPS.

- Requirement that the Airspace Modernisation process for the London airports system, with a 3rd runway at Heathrow, must be completed before the DCO hearing, allowing communities to fully understand the impact of flightpaths.

- Monetise the costs of meeting the ANAS/ANNE noise impacts (43db Leq) into the Webtag assessment, and incorporate the results into noise policy before the DCO stage.

- Assess the project against the health and science-based targets of the WHO on air pollution

- A quantitative assessment of UFPs and non-CO2 impacts of the project, according to the precautionary principle

- A guarantee that full funding for all necessary rail connections has been secured ahead of the DCO stage

- As assessment of the opportunity cost of diverting the UK’s limited investment resources and construction capability into this project, compared with other large-scale infrastructure projects such as Northern Powerhouse Rail

- A requirement to demonstrate clearly how the project will actively protect jobs and connectivity in the UK’s regions.

July 2026

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