AEF and other NGOs urge government to define dangerously “ambiguous” tests that will define airport expansion for years to come
8th June, 2026
The Government has long promised that any expansion at Heathrow Airport would have to meet ‘four tests,’ in the areas of air quality, noise pollution, economic benefit and the UK’s net zero targets. While these ‘four tests’ have long been discussed, we believe they are under-developed, ambiguous and subject to political reframing.
Now, with revisions to the Airports National Policy Statement due to be published, there is a window of opportunity to lock in clear, legally enforceable tests. AEF, alongside a coalition of NGOs, have created a briefing demonstrating what these tests would look like.
Economic impact
The airport expansion must provide:
- Clear, net economic benefits that are felt across the UK, which are not concentrated in the South East.
- Reassurance that the project does not require subsidies, tax discounts or any form of public funding (including improvements to public transport).
Noise
When it comes to the government’s test on noise, airport expansion proposals must:
- Include a comprehensive guide proposed flight paths
- It will not increase the number of people exposed to harmful noise levels.
Air
In terms of air quality, expansion plans must:
- Be assessed against health-based air pollution targets from the World Health Organization.
- Demonstrate there will be no net increase in vehicle journeys in the surrounding area as a direct result of the expansion plan.
Climate
Environmental groups believe that increasing airport capacity is incompatible with the government’s climate commitments. As such, any proposals must demonstrate they are:
- Consistent with the downward trajectory of aviation emissions in every year of Carbon Budget 6&7, and do not rely on international offset credits.
- Account for cumulative emissions from all permitted and forecasted UK airport expansions in the upcoming Carbon Budget 7.
See the full details of the tests mapped out in the briefing below:
Photo credit: Ahmet Yüksek, Unsplash