The cost of a typical family's annual energy bill could soar to £2,000 because of the volatility of the energy market and the huge investment required.
The major credit card providers say they will show mercy to borrowers who make late payments because the postal strike has delayed their bill's arrival.
The energy regulator is considering whether Scottish Power is unfairly locking customers on a popular fixed rate deal that ended last month into an expensive capped tariff.
British Gas, EDF, E.On, nPower, Scottish & Southern Energy and Scottish Power have given the strongest hints yet that there will be no price cuts this year despite rising profits.