Ofgem said energy debt would be written off "in some cases" for those customers who had a prepayment meter involuntarily installed during the regulator's review (1 January 2022 to 31 January 2023).

The typical bill will drop by £129 to £1,720 per year when the regulator's new price cap - which sets the limit on how much firms can charge customers per unit of energy - comes into force.