BRITISH GAS has been forced to fork out £1.7 million over a top-up blunder which threatened to leave thousands of vulnerable pre-payment customers without energy in winter.

Britain’s biggest energy supplier failed to inform more than 250,000 pre-payment customers about changes to how accounts can be topped up until almost a month after the switch.

The company switched in-store payment systems from PayPoint to Payzone earlier this year.

About 270,000 pre-payment customers were not properly informed of the switch, with some letters coming in late January, according to Ofgem.

The energy regulator said that as a result some people may have been left without energy over the winter.

Others would have made unnecessary trips to shops that had the PayPoint system, where they were no longer able to top up.

The British Gas helpline was also unstaffed on New Year’s Day when the switchover happened, Ofgem found.

The company has agreed to pay £1.48m to affected customers, and will pay an extra £250,000 into Ofgem’s energy redress fund.

British Gas told most of its customers of the change in December 2019, which did not leave enough time for customers to switch to a new energy supplier.

The letters also did not tell customers that the minimum top-up had been changed from £1 to £5, Ofgem said.

Citizens Advice chief executive Dame Gillian Guy branded the situation “unacceptable” and warned that it would disproportionately affect those on lower incomes and those with health conditions.

National Pensioners’ Convention general secretary Jan Shortt said that many older and vulnerable people will have had struggled, especially in poor weather, to find somewhere to top up their gas and electricity.

“Ofgem must be a lot more robust in monitoring and picking up customer service problems and dealing with them in a way that benefits those on low income, not the profiteering of British Gas,” she said.