Ofgem to limit back billing to 12 months

LONDON (Reuters) - Britain's energy suppliers will be banned from back billing customers for energy used more than 12 months ago, regulator Ofgem said on Monday.

The move comes as pricing by Britain's energy firms is under political scrutiny and a week after a law was introduced aimed at capping bills.

The new rule will come into effect at in May for domestic consumers and in November for microbusinesses, Ofgem said.

The typical back bill - which can happen due to problems with a supplier's billing systems or from incorrect usage estimates – is 1,160 pounds, it said.

"Getting billing right is an essential part of customer service, and it's unfair that consumers should be left out of pocket," said Rob Salter-Church, Ofgem's interim senior partner for consumers and competition.

Suppliers would still be able to recoup money past 12 months if customers behaviour has been unreasonable, such as blocking access for meter readings, Ofgem said.

Britain's big six energy suppliers, controlling around 80 percent of the market are Centrica's (CNA.L) British Gas, SSE (SSE.L), E.ON (EONGn.DE), EDF Energy (EDF.PA), Innogy's (IGY.DE) Npower and Iberdrola's (IBE.MC) Scottish Power.

(Reporting by Susanna Twidale; Editing by Alexander Smith)