The legal case against Heathrow’s third runway will be heard in the Court of Appeal today, when campaigners will argue that the government’s decision to expand the London airport was unlawful.

In May, the High Court ruled the government policy that approved the expansion of Heathrow was lawful, following legal challenges brought by a number of environmental NGOs, pressure groups and local councils.

However environmental group Friends of the Earth, represented by national firm Leigh Day, will argue today that the decision breached the department for transport’s sustainable development duties in failing to mitigate climate change for future generations.

Friends of the Earth is one of several appellants who will present cases over the next six hearing days. Other appellants include four London boroughs, Greenpeace, Heathrow Hub Ltd and Plan B Earth Ltd.

The case will be heard by three judges – Lord Justice Lindblom, Lord Justice Singh and Lord Justice Haddon-Cave – and is due to be live streamed here.

Rowan Smith from Leigh Day’s environmental law team said: ‘Since the last hearing in this case in March 2019 the government has legislated for net zero carbon emissions under the Climate Change Act which our client believes would have almost no chance of being met if the expansion of Heathrow was to go ahead.’

Will Rundle, head of legal at Friends of the Earth, added: ‘How can ministers even consider greenlighting high carbon infrastructure projects like the third runway at Heathrow at a time of climate crisis?

‘The government has admitted that it did not consider the Paris agreement when agreeing to Heathrow expansion. We hope the Court of Appeal will now agree with us that this is not sustainable development and ignores the needs of future generations.’