For a while, Britain’s green consensus looked ironclad. Through the 2010s and into the early 2020s, the Conservatives and Labour fought over who was keener to decarbonise the country. The public seemed eager too, so long as wind turbines wouldn’t spoil their view. Among the few decisive acts of Labour’s scattershot first year in government was an ambitious plan to turn the electricity grid green by 2030, half a decade ahead of the Tory target and speedier than any other big country.