Families face a “horrific” situation, said Scottish Power chief Keith Anderson, who has called for the cap system to be scrapped and a social tariff introduced instead, with wealthier customers paying more.
The cap rose by a record £693 per year on average in April, but prepayment customers, who are often the most vulnerable, face yet larger increases.
A deficit fund to allow people 10 years to pay off £1,000 on their bills could be a useful measure to help in the meantime, said Mr Anderson.
He is one of several bosses of the largest energy companies calling for a huge packet of support from Rishi Sunak, amid warnings that customers could end up paying as much as £1 in £6 on bills, and a third of people or more in the UK be pushed into real poverty.
Green levies should go, and VAT on energy be reduced to zero as a counter measure, the chief executives have told the Chancellor.
A price hike approaching £500 later this year could leave the average annual bill at a staggering figure of £2,450 or above.
Inflation in the UK is at a 30-year high, and living standards are set to drop lower than has been seen for decades.
The rocketing cost of living is exacerbated by effects of the Russia Ukraine war - these countries being responsible for around 15 per cent of the world’s wheat.
Analysts warn that around 7.5 million anxious households could face the dire choice of heating or eating this winter.
Mr Sunak has so far offered Britons a one-off £200 discount on energy bills in October that must be paid back over five years from 2023. This accompanies a council tax rebate and an extension of the warm homes discount, worth £150, to one million more households.
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But E.ON boss Mike Lewis said, when addressing MPs and calling for greater action, that the help meted out so far ‘isn’t nearly enough to mitigate the full impact of this price increase”.
He added:‘We expect to see the outstanding debt increase by around 50 per cent on our books - that’s what our modelling shows us - by the end of this year.”
Chief executive of EDF energy, Simone Rossi,said his company has recorded a 40 per cent increase in calls from customers concerned about their debt, while Chris O’Shea, chief executive of British Gas owner Centrica, said about one in ten of customers are late in paying their bills, translating to an estimated 716,000 customers on average being about £440 in debt ... an increase of 125,000 versus this time last year and about £50million of extra debt.