British Gas is to increase prices for 3.5 million customers, its parent company Centrica has announced.
The increase in its standard variable tariff (SVT) from 1 October means the average bill will rise by £44, taking it to £1,205 a year.
This is the second increase this year, but Centrica said wholesale energy prices had risen since the last time.
The SVT was withdrawn for new customers in March and 2.4 million customers on fixed rates are unaffected.
The company said its average bill was still “just below” the average of other large energy suppliers.
“We understand that any price increase adds extra pressure on customers’ household bills. However, this reflects the sharp rise in wholesale energy costs,” said Mark Hodges, chief executive of Centrica’s consumer arm.
Other companies had also increased their prices since April, he said.
He added that Ofgem had also announced it was raising its pre-payment meter cap – which protects vulnerable customers – from October.