Developers behind the planned Wylfa Newydd nuclear power station in north Wales have officially cancelled the project, despite saying recently that they had held “positive and encouraging” talks with multiple parties that had expressed an interest in moving ahead with new reactors at the site.

Japan’s Hitachi has told staff it will shut its Horizon subsidiary, which was to build two UK advanced boiling water reactor (UK ABWR) units at at Wylfa on Anglesey, by 31 March. The cost of the project had been put at about £20bn.

Horizon announced on Thursday it had officially withdrawn its application for planning permission for the construction and operation of the station and associated infrastructure.

In a letter to the planning inspectorate, Horizon chief executive officer Duncan Hawthorne said discussions with multiple parties “have not, unfortunately, led to any definitive proposal that would have allowed the transfer of the sites to some new development entity willing to replace Hitachi Ltd”.