Heathrow third runway health impact report warns of major local harms

The UK government has opened consultation on a revised Heathrow expansion policy alongside an official assessment warning that a third runway could cause major adverse health and social impacts for people living nearby.

The assessment, prepared by Aecom for the Department for Transport, says the scheme could worsen noise and air quality and affect access to housing, education, healthcare, open space and transport. The Guardian reported that the warning applies to as many as 3 million people in the airport area and surrounding communities.

The publication adds an official health warning to one of the UK’s longest-running infrastructure disputes, sharpening the local-impact case against the project even as ministers argue the consultation is part of a broader process to test mitigations and weigh wider economic gains.

What the assessment says

The report says a Heathrow third runway could have major adverse health impacts on the most local population if it went ahead without mitigations.

It also says the project could damage water quality, community cohesion, landscapes and townscapes. Climate mitigation and climate adaptation are also listed among the areas that could be affected.

The assessment does not amount to final approval or rejection of the airport expansion. It is part of the consultation stage for a draft Heathrow Expansion national policy statement.

The Department for Transport says the health assessment describes what would happen without mitigations and that officials are actively working to implement them.

How the policy moved

The current phase follows the government’s earlier decision to fast-track work on a revised Heathrow Airports National Policy Statement so it could go out for consultation in summer 2026.

That process moved into a more public stage on June 18, 2026, when the consultation package and the Aecom-backed health assessment were published.

The timing matters because the health warning now sits directly alongside the government’s formal consultation, rather than appearing only in campaigners’ criticism or earlier planning disputes.

The government’s case

Transport Secretary Heidi Alexander said the consultation is intended to let businesses, communities and the public help shape the project and address noise, air quality, climate change and economic growth.

Chancellor Rachel Reeves has also backed the runway as a growth project. Reporting on her remarks said the government is on track to get spades in the ground in this parliament.

According to that reporting, Reeves said the project could support more than 60,000 local jobs and deliver up to £42 billion in benefits.

The government’s argument is that the expansion should be judged not only on local disruption, but on the wider economic case and the ability to reduce harms through mitigation.

The local stakes

Heathrow’s plan still involves a 3,500-metre runway, the relocation of part of the M25 and the compulsory purchase of about 800 homes, according to The Guardian’s report.

Those details explain why the project remains so politically sensitive in west London and beyond. The health assessment adds a formal government-backed warning to concerns that have long centered on noise, emissions and displacement.

For residents and local authorities, the practical stakes include homes, roads and access to essential services around the airport corridor.

For campaigners, the assessment strengthens the case that the burdens would fall heavily on nearby communities even if the national economic case improves.

What happens next

The consultation on the Heathrow Expansion national policy statement will now run and gather responses.

Ministers are expected to refine mitigation proposals and policy wording before any later parliamentary or planning decisions.

Campaign groups and affected residents are likely to challenge whether the promised mitigations are enough, and whether the consultation meaningfully addresses the scale of the harms identified in the assessment.

Heathrow, meanwhile, is expected to keep pushing its financing, planning and deliverability arguments as the process advances.

The runway remains a proposal, not an approved project. But the publication of an official health warning means the government’s latest push to advance Heathrow expansion now carries a clearer and more immediate local-cost warning than before.