Balfour Beatty, Doosan Babcock, Laing O'Rourke and Weir have been named among the companies to build the new Hinkley Point nuclear power station in Somerset.
The firms were selected by French energy giant EDF, responsible for the £14bn development. The announcement, described as a major step forward for the first new nuclear development in the UK in more than 20 years, follows the selection of preferred engineering and construction bidders Areva, Alstom and BouyguesTP.
While the first round of contractors were all French firms, the new round involves mostly local, Somerset and UK based, companies.
It is now estimated that more than 60 per cent of the construction cost will be placed with UK firms, 3 per cent more than an initial estimate.
The more than 20 newly announced firms will divide between themselves £1.3bn worth of contracts.
"This is great news - Hinkley Point C offers a tremendous opportunity for the UK supply chain and we've worked closely with EDF to ensure British firms benefit," said Energy minister Andrea Leadsom.
The power station will provide 25,000 jobs during the construction phase, including 1,000 apprenticeships.
A final investment decision (FID) is expected in the coming months, after which the contracts will be signed, and the first electricity is expected to be generated in 2023.
Hinkley Point C will cost around £14bn to build at present costs, rising to £24bn by the time it is finished, and interest payments have been added.