The move leaves only France's EDF and China's CGN with building plans in Britain where nearly half the nuclear plants are set to shut down in the next four years.

Hitachi's UK unit Horizon Nuclear Power failed to find private investors or secure sufficient government support for the stalled Wylfa project in Anglesey, Wales.

It was expected to provide about 6% of Britain's electricity.

"Hitachi made this decision given that 20 months have passed since the suspension, and the investment environment has become increasingly severe due to the impact of COVID-19," the company said in a statement.

Hitachi last year booked a writedown of 300 billion yen due to the suspension of the 3 trillion yen ($28 billion) project.

Hitachi said it would coordinate with the British government and relevant organisations regarding the handling of the planned construction sites and other matters.

"It is imperative that a way forward is found for the site, to deliver thousands of jobs... and millions of pounds of investment... while delivering secure, reliable and low carbon power," said Tom Greatrex, chief executive of the Nuclear Industry Association.

Britain's Department for Business, Energy and Industrial Strategy (BEIS) said it recognised the news would be disappointing for the region.

"We remain willing to discuss new nuclear projects with any viable companies and investors wishing to develop sites in the UK, including in North Wales," a BEIS spokesman said via email.

EDF is building Britain's first new nuclear plant in more than two decades, Hinkley Point C, with backing from China's CGN.

EDF has called on the government to launch a new funding model to help more projects get built.

Japan's Toshiba Corp, scrapped its British NuGen project in 2018 after its U.S. reactor unit Westinghouse went bankrupt.

The decision was not expected to have significant impact on Hitachi's business results as the company has already written down most of the related assets, the company said.

By Makiko Yamazaki and Susanna Twidale