Five questions on: The 'big six' energy suppliers

Why are they in the news?

The Competition and Markets Authority accused them of penalising loyal customers by up to £234 each. Its investigation found that more than 95 per cent of customers of the "big six" – British Gas, EDF, E.on, nPower, ScottishPower and SSE – paid hundreds more than they needed to by sticking on standard tariffs rather than switching to cheaper fixed-rate deals.

Have they been ripping us off?

Anyone who hasn't switched energy supplier is paying more than they need to heat and light their home.

So why hasn't everyone just switched to get a better deal?

The CMA said those who haven't switched are "less educated, less well-off, more likely to describe themselves as struggling financially, less likely to own their own home, less likely to have internet access, more likely to be disabled or a single parent". They are also "more likely... to think switching is a hassle, that there are no real differences between suppliers, and that something may go wrong if they switch".

Is that true?

No: switching is getting easier and quicker. Energy companies have cut the time it takes to switch between suppliers to 17 days – down from five weeks last year – according to a report from the Department of Energy and Climate Change. Meanwhile, there are huge differences between suppliers, not just on cost but on the quality of their customer service.

What alternatives do I have?

There are now lots of suppliers. In fact a customer satisfaction study by the consumer group Which?, published this year, showed that none of the top 10 suppliers were from the big six. Top was Ecotricity, followed by Good Energy, Ebico and Ovo Energy. The others in the top 10 were Utility Warehouse, Flow Energy, Co-operative Energy, M&S Energy, Sainsbury's Energy and First Utility.