UK gas prices rocketed to a new record yesterday — fuelling fears a big supplier could go bust.
Sources said if a big firm went to the wall it could prove too expensive for others to take on their customers.
The British wholesale gas price for October delivery rose to 253p per therm.
That was up more than 17 per cent from the day before and means costs have more than doubled in a month.
Today marks the official start of the winter gas season when heating demand picks up.
Three smaller firms went out of business on Wednesday, taking the total to ten in two months.
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The energy price cap on household bills also rises today.
Charity National Energy Action warned that the average increase of £153 for prepayment customers, and £139 from those paying by direct debit using a default tariff, is likely to tip 500,000 households into fuel poverty.