Energy secretary Claire Coutinho is under pressure to delay the introduction of fines on gas boiler manufacturers in order to preserve the government’s wider scheme to speed up the heat pump roll out. Reports that Coutinho could scrap or delay the introduction of the Clean Heat Market Mechanism (CHMM) has sparked a “furious” backlash within the Department for Energy Security and Net Zero (DESNZ), it is understood. Utility Week has learnt that long serving energy efficiency minster Lord Callanan threatened to resign over the mooted volte-face alongside energy security minister of state Graham Stuart.