Exclusive: Officials working on further radical changes that would change how much energy companies could charge customers

John Healey is planning a major intervention to cut energy bills for poorer households in this month’s budget, after ministers became alarmed at forecasts that show bills rising by hundreds of pounds in January.

The chancellor is working on plans to spend more than £1bn to help energy consumers, the bulk of which is likely to go towards increasing the discount given to households on certain benefits.