The annual statements to be introduced by energy suppliers are likely to be too confusing, an industry watchdog has warned.
According to Consumer Focus, the annual energy statements it has seen, which are due to be introduced later this year, do not provide customers with enough information to switch energy tariffs and get the best deal possible.
The watchdog said some of the statements are still confusing and are not clearly labelled, making it difficult for customers to make sense of them.
Audrey Gallacher, head of energy policy at Consumer Focus, told BBC News: "Some are very good, others could do much better.
"Some companies are applying the letter of the regulations but not the spirit - and the spirit is that people get information to manage energy use and make comparisons."
Scottish and Southern Energy and npower's statements were classed as poor, while Scottish Power's efforts were identified as average. E.ON and EDF were praised for their statements, with British Gas coming out on top.
The Energy Retail Association, which represents energy suppliers, said the statements are a "work in progress".
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