The energy regulator Ofgem told BBC's Money Box that it is writing to chief executives demanding to know how many people have been sent "back bills". Back billing is when customers receive new bills for energy used longer than 12 months before - a practice that was banned seven years ago.

A report by consumer watchdog Citizens Advice claimed that network operators made use of a regulatory loophole set by Ofgem

OFGEM has required energy suppliers to offer tariffs with low or no standing charges, allowing customers to pay costs as part of the unit rate. This change aims to give consumers more flexibility and potentially lower their energy bills.

Every energy supplier could be required to offer tariffs with low or no standing charges, under new proposals from the energy regulator

Ofgem has announced plans to introduce low or no standing charge energy tariffs, aiming to provide customers with greater control over how they pay for electricity and gas. The proposal is currently under consultation,

British energy regulator Ofgem has proposed that energy suppliers offer tariffs with low or no standing charges, integrated into the unit rate. This change aims to provide consumers with more flexibility in managing their energy bills.

Standing charges are set by energy suppliers and rack up daily, regardless of how much energy you use that day.