Hitachi has suspended work on a new nuclear power station in Wylfa, north Wales.
Thousands of jobs are at risk after the company halted plans due to rising construction costs.
Talks were held with the UK government regarding funding, but no terms were agreed.
Construction union Unite has hit out at the government over the project, calling this announcement "the latest chapter in the sorry saga of recent UK energy policy".
Unite national officer for energy Peter McIntosh said: "This government should be held to account as it has no coherent policy and has, yet again, let the country down. The lights are going out when it comes to energy policy.
"There are very real concerns over how we will keep the lights on for industry and consumers in the coming decades.
"Without Wylfa being built, there is no way the country can meet its climate change obligations which it committed to when it signed up to the Paris Agreement in 2016.
"We need to replace the current generation of nuclear plants and Wylfa is a key part of that programme.
"Business secretary Greg Clark needs to step up to the plate and recalibrate energy policy with a vigorous commitment to substantial government funding for large-scale energy infrastructure projects."
The suspended work in Wylfa follows the withdrawal of Toshiba from the Moorside nuclear power station project in Cumbria in November.
Unite has pinpointed this and a few other occasions as factors that are leading to a crisis in UK energy policy.
Unite Wales regional secretary Peter Hughes added: "This is devastating news for the Welsh economy and, in particular, that of north west Wales. The future regeneration on the region has been based upon the bedrock that Wylfa Newydd would proceed.
"For that to now be suspended is a hammer blow to the future prospects of some of most economically deprived communities in the whole of Wales.
"Although this decision has ultimately been made by Hitachi, the UK government must take a massive share of the blame. It has failed miserably to put its full weight behind this bid and to effectively advocate the case for Wylfa Newydd.
"For the prime minister Theresa May to fail to raise Wylfa Newydd with the Japanese prime minister Shinzo Abe last week was shameful.
"The UK government's complete obsession with its disastrous Brexit strategy has meant it has completely took its eye off the ball in getting this crucial infrastructure project over the line.
"Theresa May's government is failing Wales at every turn."
(CM/JG)
Construction News
17/01/2019
Hitachi Suspends Work On UK Nuclear Power Station


30/06/2025
Places for London, Transport for London's wholly owned property company, has announced Ballymore as its joint venture partner for the transformation of the Limmo Peninsula in east London.
The partnership will see the creation of around 1,400 new homes, spanning affordable, market, and rental tenur

30/06/2025
Balfour Beatty, in partnership with Laing O'Rourke and Bouygues Travaux Publics, has officially signed the Programme Alliance Agreement with Sizewell C to deliver the main civil works at the UK's next nuclear power station.
The three companies will operate as the Sizewell C Civil Works Alliance (CW

30/06/2025
Morgan Sindall Construction and Southampton City Council have officially broken ground on the £36 million transformation of the city's historic Outdoor Sports Centre, marking a major milestone in one of the region's most ambitious regeneration projects.
A ceremonial event to celebrate the start of

30/06/2025
Doncaster Council has officially received a new collection of affordable homes at the Nutwell Grange development in Armthorpe, as part of a housing partnership with housebuilder Persimmon.
Deputy Mayor Glyn Jones and Councillor Majid Khan visited the site this week to mark the handover of eleven on

30/06/2025
Winvic Construction Ltd has announced the shortlisting of seven awards at this year's prestigious 'Inspiring Women in Construction and Engineering Awards' (IWCE).
The shortlist celebrates both individual excellence and Winvic's company-wide commitment to advancing equity and inclusion in the built

30/06/2025
Alder Hey Children's Hospital and construction partner Morgan Sindall are celebrating a significant milestone in the development of a new facility that promises to transform care for children and young people.
The structure of the new building, which will house a state-of-the-art surgical neonatal

30/06/2025
Henry Boot PLC has announced that its land promotion and planning arm, Hallam Land Management, has completed the sale of a freehold site in Yalding, Kent, to housebuilder Fernham Homes.
The site has full planning permission for 112 residential units.
The sale has generated an ungeared internal ra

30/06/2025
A St Mungo's care home in Islington for people affected by homelessness has reopened its doors after a transformative refurbishment delivered by volunteers from delivery consultants and construction specialists Mace.
The six-week project, led by 46 Mace volunteers, saw the complete redesign and re-

30/06/2025
Galliford Try has marked a key construction milestone at its flagship project, The Rise, with a topping out ceremony celebrating the completion of the building’s structure at Guildford Crescent in the heart of Cardiff.
Once completed, The Rise will become Cardiff's tallest building, delivering 272

30/06/2025
Thousands more young people in the North East will be trained for careers in the fast-growing green energy sector thanks to an £8.48 million investment approved by North East Mayor Kim McGuinness and her Cabinet.
The funding will support the expansion of Newcastle College's Energy Academy in Wallse