A group campaigning against the construction of a Suffolk nuclear power station has won a court victory.
Together Against Sizewell C had argued the government had failed to assess the environmental impact of the project when granting planning permission.
A High Court judge dismissed its calls for a judicial review on 22 June.
The Court of Appeal overturned this ruling, based on arguments around the lack of a permanent water supply for the site.
Lawyers for the group of residents said this was "essential" for the operation of the plant.
Lord Justice Coulson dismissed other grounds for the appeal.
Jenny Kirtley, chair of the group of local residents, said: "[We] are delighted by the appeal court's decision and welcome the acknowledgement that our appeal, challenging the secretary of state's approval of Sizewell C, has a 'real prospect of success'."
French energy giant EDF, due to develop the project, said: "These claims have been dismissed twice in the High Court and we will support the government in defending its decision to award the development consent order for this critical piece of national infrastructure."
The government is supporting the project with a £700m stake. It has made £511m available to continue project development and prepare the coastal site for construction.
A formal invitation has been sent out for investors to come forward to help fund the project, which is thought to be costing upwards of £20bn.