An anglers’ pressure group has won a landmark legal ruling confirming that the company building Hinkley Point C cannot refuse to answer environmental information requests simply because it is privately owned.

A London tribunal ruled this week that NNB Generation Company, the EDF subsidiary responsible for Hinkley Point C, must now respond to requests for information about the power station’s cooling water intake, environmental protection measures and possible environmental compensation.

A spokesperson for the pressure group Fish Legal, which uses environmental law to protect rivers, lakes and coastal fisheries on behalf of anglers, said: “The company must now either provide the information or identify specific legal grounds under environmental law for withholding it”

“The judgment confirms that when a private company is entrusted with major public functions and granted exceptional statutory powers, private ownership does not necessarily place its decisions beyond public scrutiny.

“The ruling may influence future cases involving other private companies exercising comparable functions and powers.”

Zoe Wedderburn-Day, head of policy and strategy at Fish Legal, said: “The new government wants essential infrastructure built more quickly. Much of that programme will depend on private companies using powers granted to them by the state.

Those companies cannot be given exceptional public powers and then close the door when people ask how the powers are being used. Public confidence depends on meaningful transparency and accountability."

Ms Wedcderburn-Day added: “This judgment does not decide which environmental protection technology should be used at Hinkley Point C. It confirms that NNB cannot avoid answering environmental information requests simply by saying that it is a private company.

“The immediate issue is whether the company will now provide the information or explain clearly why it believes any part of it should remain withheld.”

NNB may seek permission to take the case to the Court of Appeal.