Energy prepayment customers have yet to claim £64m in energy vouchers sent to them to help with the cost of living - with £17m due to expire in the next few days.
The Post Office, which processes the vouchers on behalf of most energy companies, is urging households yet to cash their October £66 voucher to claim before it's too late.
Most households are entitled to the £400 energy bill discount announced by former Chancellor Rishi Sunak in May last year, designed to take the sting out of the planned October price cap increase, which would have seen bills soar to £3,549 a year. Bills have since risen to £4279 on average, but energy price guarantee means that the price for the average household is capped at£2,500 a year.