The company has also stated that its customer service record has improved, with the level of complaints about the company sent to energywatch falling by 80 per cent between April and December.
Sam Laidlaw, the chief executive of British Gas owner Centrica, said last year was one of "substantial achievement" for the company.
He added that the company had made progress on "addressing key priorities for the business".
In recent weeks, British Gas has been one of five major energy suppliers to increase the price of its gas and electricity.
The company blamed its decision to up the price of its tariffs by 15 per cent on rising wholesale oil and gas prices.
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