The chief executive of Scottish Power has said energy price rises later this year are going to be "horrific".
Keith Anderson told MPs at Westminster "so many people are really going to struggle".
The BBC reports him as saying the 54% increase in the energy price cap was already affecting customers and another steep rise is expected in October.
Mr Anderson said his company had 8,000 calls last week to a hotline for people worried about their ability to pay.
The Scottish Power chief appeared before the House of Commons Business, Energy and Industrial Strategy Committee alongside the bosses of E.ON, EDF and Centrica, which owns British Gas.
Mr Anderson said it was too soon for people to have run up large debts as a result of the April price rise but there was a "massive anxiety" about what they were going to do to cope with the soaring costs of gas and electricity.
He said a lot of people were facing the issue for the first time.
Mr Anderson said: "My biggest concern is when we get to October, particularly among the most vulnerable and the poorest.
"In summer consumption goes down. Come October that's going to get horrific, truly horrific."
Mr Anderson said the size and scale of the problem was beyond anything he could deal with or indeed his industry.
He called for a significant shift in government policy and approach.
The Scottish Power boss said the government should set up a "deficit fund" and wipe £1,000 off the bill of anyone who is deemed to be in fuel poverty and on pre-payment meters, which would be repaid over 10 years by all customers or the government.