The massive Moorside project was thrown into doubt when main backer Toshiba ran into financial problems and warned it was calling time on all future planned nuclear power station projects.

Kepco’s announcement, made in South Korea on Wednesday, will save the £15bn project but see the building programme slip back.

The firm, which ranks as the world’s fifth biggest nuclear power producer, said it planned to negotiate with Toshiba over the next few months to buy a stake in the nuclear project and sign a deal in the first half of next year if the negotiation progresses smoothly.

Moorside’s developer had planned to build three reactors at the site near Sellafield using Toshiba company Westinghouse’s AP1000 reactors.

Its replacement with Korean technology will need fresh regulatory approval which is expected to push the timetable for completion from 2025 to the end of the decade.

The boost for nuclear power station building comes as the Government prepares to make an announcement today which is expected to back the development of small-modular nuclear reactors in the UK.