Britons are being warned of a stark rise in scammers impersonating energy giant British Gas to steal personal information and banking details on the pretence of offering savings or assistance with bills.

The Phonely Who Called Me? platform, which tracks thousands of suspicious calls daily, has reported an “inundation” of alarming reports from people being preyed on.

One person said: “A man claimed to be from British Gas, asking to book an appointment to check if I can save on my…