The project was granted permission to build in July 2022, allowing some preparatory works to subsequently begin.

But the government also set out several obligations that needed to be satisfied before construction could commence on the plant, including key road surveys and the establishment of governance groups. These have now been completed.

Before construction can start, the government must raise £20bn from outside investors through a mix of debt and equity, with the cost clawed back through a surcharge on energy bills while it is being built.

Last September, the Government, Sizewell C and electricity giant EDF launched an equity raise process to attract private investors into the project.

While triggering the DCO and entering the construction phase is not dependent on a final investment decision (FID), constructive discussions with qualified potential investors are continuing and a final investment decision is expected later in 2024.

Julia Pyke and Nigel Cann, joint managing directors at Sizewell C, said: “This is a significant moment for our project in Suffolk and a big step for British energy security.

“We’ve had a really successful year of pre-commencement works on site, and we’ve been working hard with local partners and organisations to ensure we’re ready to take this next step for the project.

“While Sizewell C will be a linchpin of Britain’s energy system, it’s much more than a power station, especially for this region.

“Entering the construction phase will be a game-changer for the area, helping to boost employment and skills, enhancing the local environment, and developing new clean technologies.”

Nuclear Minister, Andrew Bowie, said: “This is a major milestone for Sizewell C and our ambition to deliver up to 24GW of low-carbon nuclear power by 2050.

“It comes after we announced the biggest expansion of nuclear power for 70 years, which will help to bring down bills and bolster our energy security. East Anglia will benefit from thousands of new jobs and apprenticeships as a result, demonstrating the local rewards of backing new nuclear.”

Mark Burrows, regional commercial director of Suffolk-based Breheny Civil Engineering, said: “This vast nationally strategic project offers us within Suffolk the chance to showcase our extensive talent and resources and will provide work opportunities for many years.

“We’re already participating in projects on the Sizewell complex, and we look forward to working on many more opportunities. Our 330+ people and their families live and work in the geographical area affected by Sizewell and are looking forward to the social, environmental, and economic benefits the project will provide our community.”