British Gas may customers may have been over-charged for up to five years on part of their bills.
Major supplier EDF Energy has expressed its support for proposals to help consumers find the best deals and save money.
Which? ConversationScrapping standing charges
Do you pay a standing charge for energy? If so, would you like to see it scrapped in favour of simpler prices?
Which? adviceHow to use less electricity
Looking to reduce the size of your electricity bill? Make a great start with help from our energy-saving experts
Essentials & tips
Get clued up on the Green Deal
The Green Deal is the government's flagship energy efficiency scheme - find out more.
Don't get overcharged on energy
See our top tips on how to avoid getting overcharged by your energy company.
Energy labels explained
Confused by energy labels? Find out all you need to know with our simple guide.
Energy saving tools and calculators
From washing machines to batteries, find out how to recycle electrical items with our product recycling tool.
Find out how much your appliances are costing you to run with our easy to use cost calculators.
Has your washing machine developed a fault? See if it can be fixed using our free troubleshooter.