Sat at the back of the Supreme Court this week, while cheers erupted with the announcement that the panel of judges had unanimously ruled in favour of Client Earth's air pollution case, it is possible to imagine a member of the audience hurriedly typing out a message to his or her colleagues.
It reads: "we may have a problem".
That person could be a member of the Airports Commission staff and he or she would know that the ruling could mean the end of Heathrow's third runway scheme and possibly even Gatwick's bid for a second runway.
The Airports Commission, tasked with making recommendations on the future of UK airport capacity could already have written its final report, recommendations finalised, and be waiting for the post-election humdrum to die down before the report would be launched into the public sphere. The Supreme Court ruling changes that.
There is now a serious challenge to any recommendation to build a new runway, particularly (but not only) at Heathrow. Around the airport, the area is in breach of legal limits for NO2 pollution today and has been for many years. Modelling released by the Government's environment department revealed that the area around Heathrow is forecast to continue breaching legal limits up to 2030, that's with just two runways.
The Airports Commission has concluded that expanding either Heathrow or Gatwick would have a negative impact on air pollution through increases in air traffic and cars and taxis needed to carry passengers to and from the airport. This should mean that under law, planning permission for Heathrow (and possibly even Gatwick) should be refused as is the case for all developments that will cause air quality limits to be breached, or make air quality worse in an area where pollution already exceeds the limits.
But until now, there has been little reason for the Commission to think that this represented a meaningful barrier to airport expansion. The UK has been in breach of air pollution laws for some time and the Government claimed that it would take time to put in place effective measures to tackle air pollution. Being compliant with legal limits by 2030 was the latest estimate.
The Government's stance was firmly rejected this week by the Supreme Court when it ordered the Government to produce a new action plan by the end of this year for bringing air pollution within legal limits. Any decision to expand Heathrow could be legally challenged unless the Government's new plans are sufficiently ambitious to reduce emissions below the legal limit and leave enough headroom to accommodate the negative impact of an additional runway. That is a tough ask and it is pure speculation about how it could be achieved.
The court ruling also suggests that the cost-benefit analysis for expansion will need to be revised since the Government has previously claimed that complying with air quality law would be too expensive. The cost of having to take additional mitigation measures to accommodate increased emissions from a new runway under legal limits should be added to the cost-benefit analysis of a new runway.
Does the court's decision open the door to a Gatwick runway? Not necessarily. EU regulations require not only that poor air quality must be improved but also that good air quality should be protected. It has been estimated that if all of the local jobs predicted by the Airports Commission materialise following Gatwick expansion, there would be an additional 100,000 vehicles using roads around the airport each day. That could create an air pollution hotspot around Gatwick. The lower background air pollution means that there is a lower risk of breaching the legal limits but a risk still remains.
The Airports Commission, as an independent but taxpayer funded organisation, has a duty to the public not to recommend a project that would significantly damage people's health. It would also be a poor use of taxpayer's money to make recommendations that invite a legal challenge. That is why it is possible to imagine a concerned Airports Commission member of staff hurriedly typing away on his or her phone at the back of the courtroom this week.Suggest a correction