It’s new. It’s shiny. It’s green. And companies from round the world are watching. British energy users will soon have to join a pioneering scheme aimed at drastically cutting carbon consumption. The system targets any non-residential users burning more than 6,000 megawatt hours a year (a power bill equivalent to about £500,000). About 20,000 organisations will be involved, from schools to town halls to businesses. Any UK headmistress or chief executive who has not been following traded carbon prices will soon do so. Just so you know, they have rallied lately.

The UK scheme is unusual in that it seeks to encourage users to compete with each other over how much they save. Take a test company, Wanna-be-Greener Plc, with a £500,000 annual electricity bill, perhaps the same size as sandwich shop chain Pret a Manger. From next April, it will have to buy £40,453 of carbon allowances from the government, at £12 each. Six months later, Wanna-be-Greener could recoup that expense according to a formula. If it has saved more energy than others, it will be repaid more – as much as 10 per cent extra, increasing to 50 per cent over five years. If it has done worse, the converse is true.