If a week is a long time in politics, then 2023 belongs to a different age in the politics of Net Zero. Less than eleven months ago, the government was saying that ‘Net Zero is the growth opportunity of the 21st century. Earlier this week, former IMF chief economist Oliver Blanchard effectively poured water on that claim when he told the House of Lords Economic Affairs Committee that there would be a ‘substantial fiscal cost to achieve anything close to Net Zero’.