Energy costs £330 more than next door?

Andrew Milligan/PA Archive/Press Association Images

Up to 5 million people may face bills up to £330 higher for using exactly the same amount of energy as the people next door. A report from the Institute of Pubic Policy Research found that those who are least aware of their bills are the most likely to be paying over the odds.

So where do these huge variations come from, and what can we do about it?