From today, consumers must be told about energy price rises 30 days in advance, rather than being notified up to two months after the price hike is implemented.
Previously, suppliers could wait for up to 65 working days after increasing prices before telling consumers. The new regulation from Ofgem is intended to provide a fairer deal for customers, and also covers any change to a contract that will leave a customer significantly worse off.
The issue was first raised by the Liberal Democrats in 2010. The Labour government pledged to reduce the delay to 10 days. However, Ofgem has gone further than expected with its new regulation.
"It is absurd that providers have been able to announce price rises retrospectively," says Mark Todd, director of energyhelpline.com. "Imagine going to a supermarket and being charged £90 for groceries and then being told three months later that actually the price was £100 and that they now wanted an extra £10. There would be uproar."
Following a recent energy review, Ofgem concluded that energy suppliers must also provide customers with simpler tariffs to limit confusion and enable customers to compare prices.