The £200m deal will see O’Rourke deliver the lagoon’s 410 metre turbine house and sluice structure block.

Up to 500 workers will be on site at peak construction with concrete, reinforcing and other materials set to be sourced locally.

O’Rourke has named Arup as its lead design and engineering partner for the contract.

Former Balfour Beatty chief Andrew McNaughton is Director of Engineering & Construction at the client and will lead delivery of the £1bn Swansea Bay Tidal Lagoon.

He replaced ex-O’Rourke director Steve Hollingshead who left the lagoon project last month to run J Murphy & Sons.

McNaughton said: “Announcing that Laing O’Rourke is joining the team is a major step forward for the project.

“As preferred bidder, their contribution over the next few months alongside General Electric and Andritz Hydro will be invaluable in preparing for delivery on site in 2016.”

Jonathan Adams, Project Lead at Laing O’Rourke said: “From London 2012 to St Pancras International Station to Heathrow Terminal 5, we’ve been involved in the delivery of some of the UK’s most celebrated infrastructure projects.

“Today, the Swansea Bay Tidal Lagoon is the talk of the international construction industry and we are thrilled to be playing a part in its delivery.”

Following advanced works and value engineering, a fixed price contract will be signed later this year for the main build.

Tidal Lagoon Swansea Bay Plc has also run tenders for the project’s marine works package and for a package to provide public realm ancillary works with the results due shortly.

Further tenders for the construction of a Turbine Assembly Plant in Wales, and for the lagoon’s public realm and buildings work will proceed through the summer.