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Legal landscape: Heathrow’s Supreme Court victory does not clear third runway for take-off

Heathrow may have cleared a legal hurdle that was blocking the path to a third runway, but others remain, say Eleanor Reeves and Kathryn Hampton 

A third runway at Heathrow airport has been controversial since the idea was first aired. The government’s support for the new runway was set out in the 2018 Airports National Policy Statement (ANPS), which sets out the national policy that governs the construction of a third runway at Heathrow. It is significant because any application for development consent for the runway will be considered against this policy.  

Campaigners challenged the lawfulness of the ANPS and initially won in the Court of Appeal, but the decision was overturned by the Supreme Court on 16 December 2020. The Supreme Court’s judgment means that Heathrow Airport will be able to apply for a development consent order (DCO) for the third runway, with the support of a lawful ANPS.

The ANPS became national policy in June 2018. At that time, the Climate Change Act 2008 set a target of an 80 per cent reduction in 1990 greenhouse gas emissions by 2050. In November 2016, the government ratified the Paris agreement, which enshrined a stronger international commitment to mitigating climate change and aims to achieve net-zero greenhouse gas emissions from 2050.

However, it was not until a year after the adoption of the ANPS that the government passed legislation to replace the 80 per cent target with a net-zero target, announcing that the UK was the first major economy in the world to do so.  

The legal challenge to the ANPS was pursued by the Mayor of London, five local authorities and several environmental groups. Having lost their case in the High Court, the claimants won on appeal on one ground relating to climate change.

“The court unanimously concluded that the ANPS was lawful, but the journey to a third runway has only just begun”

On this point, the Court of Appeal said that the ANPS should have taken the government’s commitment to the Paris agreement into account, not just the targets under the Climate Change Act 2008. As a result, the ANPS was unlawful and of no legal effect. Heathrow Airport Ltd appealed to the Supreme Court.

The Supreme Court allowed Heathrow’s appeal. It was satisfied that the Secretary of State for Transport acted rationally and in compliance with his legal obligations. The secretary of state’s report accompanying the ANPS referenced the UK’s obligations under domestic and international law and the Supreme Court said he did not need to go into more detail.

The court unanimously concluded that the ANPS was lawful, but the journey to a third runway has only just begun. Decision-makers will have to take the current (net-zero) climate change targets into account when determining the DCO and campaigners are threatening to take the issue to the European Court of Human Rights, so watch this space.

Things are certainly moving at pace. Since the Supreme Court hearing, the government has announced its commitment to meeting interim net-zero emissions targets, including a 68 per cent net reduction in emissions by 2030, and in partnership with Italy, the UK is hosting the next climate change conference (COP26) in November 2021.

Hot on the heels of the Supreme Court’s ruling, another campaign group has urged the secretary of state to review the ANPS in line with the 2030 and 2050 targets. Pressure remains on decision-makers when approving major projects in line with these overarching climate targets. They will certainly need to keep abreast of their various legal duties and requirements, and could be in for a bumpy ride.  

In brief

  • Heathrow Airport won an appeal against a ruling making a proposed third runway unlawful on environmental grounds 
  • The new ruling found the government’s disputed ANPS was lawful, opening the way for a third runway 
  • But Heathrow will now have to contend with even stiffer climate commitments that have been made since its initial proposal

Eleanor Reeves is partner and Kathryn Hampton is senior expertise lawyer with Ashurst LLP

Image credit | Shutterstock


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