EDF, the French energy firm building Hinkley Point C, is reportedly trying to raise an additional £4bn to fund the megaproject as costs continue to spiral.

According to Bloomberg, EDF is seeking to raise funds by offering investors a stake in the project, although it has pledged to return their funds if the construction is not completed. The interested parties include infrastructure and sovereign wealth funds.

Once complete, Hinkley Point C will be the UK’s first new nuclear plant in a generation. Its two nuclear reactors are expected to be able to generate enough low-carbon electricity to power around six million UK homes.

However, the project has faced repeated delays. In 2013, EDF estimated that the plant would begin operations by 2023. It now says the first generator won’t be ready until 2029 at the earliest, and potentially as late as 2031. The second generator will take around a year after the first one is brought online to become operational.

Cost estimates have also risen to least...