The future of a new Cumbrian power plant is in doubt, after one of the key players admitted it is reviewing its involvement.

A spokesman for Toshiba - which holds a 60 per cent stake in Moorside developer NuGen, alongside ENGIE of France - said it is re-examining all of its nuclear projects outside Japan.

This includes the proposed nuclear new build at Moorside, near Sellafield.

Last month Toshiba announced its US subsidiary, Westinghouse Electric, may have overpaid - by several billion dollars - for another nuclear construction and services business. Following this, its shares fell dramatically.

Toshiba confirmed yesterday it is now reviewing its involvement in all other overseas projects as a way of dealing with this situation. It also plans to sell its semiconductor business.

Its president and chief executive Satoshi Tsunakawa said: "Going forward, we will revise the positioning of the nuclear business as our main focus business in the energy sector, and review the future of nuclear businesses outside Japan."

"In Japan, we will continue business in respect of resuming operations of idled plants, maintenance services, and decommissioning of nuclear plants, as one of our social responsibilities.

"In connection with this, we are considering to separate the nuclear business from the Energy Systems and Solutions Company, and position it as an organisation directly under the control of the president and chief executive, as a measure to strengthen risk management.

"This will allow smoother reporting and decision-making and promote more information sharing, and also support us in our goal of securing stronger management of U.S. nuclear project costs and enhanced governance of Westinghouse."

A spokeswoman added: "At this moment, we can only say that we are reviewing [the] future of our nuclear power business outside Japan, but nothing has been decided at this time, including the impact on our Moorside nuclear project.

"We are reviewing broadly about our nuclear power business, and we think we can be more specific after February 14, when we plan to announce our third quarter business results that also include the amount of goodwill and it's write-down related to Westinghouse’s acquisition of CB&I Stone & Webster in 2015."

Stewart Young, leader of Cumbria County Council, said: "I would be very concerned if this had any impact on NuGen.

"We will be seeking further information about their position and will be concerned if they is any effect on what would be the biggest single private sector investment that Cumbria has ever seen."

To compound matters, Toshiba is also embroiled in an accounting scandal and it was yesterday (Monday) announced that several Japanese banks may be about to launch a lawsuit against it.

A decision on whether to proceed with Moorside is due in 2018.

A spokesman for NuGen said: “NuGen’s shareholders, (Toshiba and Engie) are committed to the development of the Moorside project.”

If Moorside does go ahead, Westinghouse, which was once owned by British Nuclear Fuels, would supply three of its AP1000 reactors.

When fully operational, they would have a combined capacity of up to 3.8GW, enough to power 6m homes and supply 7.5 per cent of the UK's electricity needs.

The first is due to come online in the mid-2020s.

Up to 6,000 people would be working on the Moorside site at any one time.