The High Court has dismissed arguments against Heathrow expansion and found that the Government is free to ignore the Paris Agreement on climate action until it forms part of UK law.

The High Court rejected all five legal challenges against transport secretary Chris Grayling's decision to allow a third runway at Heathrow Airport. In response Mr Grayling called on local authorities not to waste any more public money pursuing legal challenges.

The collection of legal claims was brought by five councils, as well as London mayor Sadiq Khan, environmental campaign groups including Greenpeace and Friends of the Earth and a private individual - all of whom opposed any expansion of the airport. A case was also brought by the promoters of a rival Heathrow expansion scheme.

The judges dismissed objections to the transport secretary’s decision to approve the Airports National Policy Statement (ANPS), which backs Heathrow expansion. The claims were brought on the grounds of climate change, air quality, surface access, noise, and habitats and that Mr Grayling had been wrong to choose the North West Runway Scheme. However the judge ruled that these were not grounds to object to expansion.

Expansion of the airport will still require a development consent order (DCO) however and any application for a DCO will be subject to examination by independent inspectors.

‘It is open to parties to contend at the DCO stage that (e.g.) the particular proposed development should not be allowed because of its adverse effects on the environment. Any decision by the secretary of state to grant a DCO may also be the subject of a legal challenge on the grounds of error of law,’ the judges said.

On the issue of climate change, the claimants had argued that Mr Grayling had acted unlawfully by not taking into account the Paris Agreement but ‘faced an overarching difficulty which, in the event, they were unable to surmount’.

The judges pointed out that the agreement ‘does not form part of UK law and so, while the UK has ratified it, until Parliament decides if and how to incorporate the Paris Agreement target, it has no effect in domestic law’.

They added however, ‘at the DCO stage this issue will be re-visited on the basis of the then up-to date position’.

The claimants also argued the government was wrong to conclude expansion could be undertaken without breaching the UK’s obligations under the Air Quality Directive.

Mr Grayling had failed to apply the precautionary principle, had acted irrationally by adopting a policy that was probably undeliverable within the Directive, and relied upon unjustified assumptions about the deliverability of public transport schemes and the effectiveness of Clean Air Zones, the claimants said.

However judges found that none of these grounds was arguable

John Stewart, chair of campaign group HACAN, said that many local authorities and campaigners will be expected to challenge the expansion plans at the DCO public inquiry, which is likely to begin next year.

This article first appeared on Transport Network