Hitachi has announced it will suspend work on a multi-billion pound nuclear plant in the UK.
The decision follows speculation that it would scrap the £20bn Horizon nuclear facility because of concerns over rising construction costs.
The Japanese firm had been in talks with the UK government about funding since June.
The decision puts thousands of jobs at risk if the Wylfa Newydd plant in Wales is scrapped entirely.
About 9,000 workers had been expected to be involved in building two nuclear reactors, which were due to be operational by the mid-2020s.
The new nuclear plant had been intended to have a generating capacity of 2,900 MW and have a 60-year operational life.
The decision puts the UK’s nuclear policy under fresh scrutiny.
In November, plans to build a nuclear power station at Moorside in Cumbria were halted after Toshiba announced it was winding up its NuGeneration subsidiary, which was behind the project.
If the Wylfa Newydd project is scrapped, it leaves the Hinkley Point power station in Somerset as the only new UK reactor still being built.
The British and Japanese prime ministers met earlier this month, but did not discuss the Wylfa Newydd nuclear power plant.
“We have been working with them, but it will be a commercial decision for the company,” Prime Minister Theresa May said at the time.