It comes after Boris Johnson struck a more upbeat tone about Cop26 progress on Tuesday, saying world leaders had scored a goal or two after his metaphor at the weekend of being 5-1 down in the contest against climate change.

But he also kept up the pressure as he left the summit, warning that targets could be “100 per cent pointless” if not followed up with action, and saying “economic catastrophe” awaited if global warming is not curbed.

There was also a blow to the Prime Minister’s hopes of limiting global warming to 1.5C as China, the world’s largest polluter, called for a less ambitious target of 2C.

The UK has vowed to become “net zero” in carbon emissions by 2050 and urged other countries to do likewise.

Scores of Western countries have also made the commitment, but developing, high-polluting countries have not gone that far, with China targeting 2060 and India picking 2070.

Hundreds of companies would be impacted by the new rules if adopted, with every UK financial institution and listed company being bound by them.

A Treasury press release said the companies would have to publish “net zero transition plans” but it remains unclear how much detail would be required.

It is expected such plans would need to involve “high-level targets” for becoming greener, “interim milestones” and “actionable steps” on delivery, according to the Treasury release.

The details will be worked out by a Transition Plan Taskforce made up of industry and academic leaders, regulators and civil society groups.