Subsidy deals are structured as contracts for difference (CfDs), which guarantee developers a “strike price” for the power they generate.

When power is sold for less than the agreed price the Government tops it up, while companies are required to pay back the difference when prices go above that level.

These deals are used across the offshore wind industry as a way to guarantee a project’s long-term income and make the projects less risky for investors to support.

Since Hornsea 3’s CfD and others were agreed, the offshore wind industry has been buffeted by surging costs and there are fears that some projects will be loss-making for years into the future.

Some schemes have already been put on hold, including Vattenfall’s Norfolk Boreas project.

On Friday, bosses at Ørsted told financial analysts they were examining an option to pass over 25pc of the CfD contract so the company would instead be free to sell power from the scheme for a higher market rate.

This could potentially boost returns from the scheme – assuming the company can secure better prices for the power privately than what it is guaranteed under Hornsea 3’s CfD.

Ørsted, the world’s biggest offshore wind developer, has insisted it intends to press ahead with Hornsea 3 in “all scenarios” but has yet to take a final decision.

The project is scheduled to begin generating in 2026 and has been awarded a subsidy deal worth about £45 per megawatt hour in today’s prices – less than what was offered in the most recent subsidy auction.

The pool of potential buyers for the 700 megawatts of power on offer is likely to be confined to heavyweight companies with big electricity demands.