The expected confirmation of approval for a significant stake in Sizewell C is designed to send a signal to investors that the Government is serious in its intent to build a new generation of nuclear power stations.

On Wednesday night, sources said negotiations were still ongoing with French state-owned EDF, the developer of Sizewell C. EDF wants to take a further 20 per cent stake as part of an agreement to remove a Chinese state-backed energy group from the project.

The new power station, to be situated alongside an existing one, would generate electricity for six million homes. A source said plans for the 20 per cent stake were close to being finalised and could be mentioned in Mr Johnson’s speech if agreed in time.

The British energy security strategy, announced in April, sets out plans to scale up and accelerate clean, affordable and secure energy made in Britain, from North Sea oil and gas to nuclear and offshore wind.

This includes a significant new approach to nuclear by delivering eight new nuclear reactors in the UK at a pace equivalent to one a year instead of one a decade. 

The Government also plans to go further and faster on renewables such as wind, solar and hydrogen, which could see 95 per cent of electricity being low carbon by 2030.

The UK has stepped up production of domestic gas – 26 per cent more this year than last – and the North Sea Transition Authority plans to launch another licensing round in the autumn, meaning more domestic gas on the grid sooner.

Earlier this week, the world’s largest offshore wind farm, Hornsea Two, off the coast of Yorkshire, became operational – set to generate enough electricity to power 1.3 million homes.